Well-designed AP 6th Class Maths Guide Chapter 12 Ratio and Proportion Exercise 12.1 offers step-by-step explanations to help students understand problem-solving strategies.
Algebra Class 6 Exercise 12.1 Solutions – 6th Class Maths 12.1 Exercise Solutions
Question 1.
There are 20 girls and 15 boys in a class.
a) What is the ratio of number of girls to the number of boys?
b) What is the ratio of number of girls to the total number of students in the class?
Solution:
Number of girls in the class = 20
Number of boys in the class = 15
a) The ratio of number of girls to the number of boys = \(\frac { 20 }{ 15 }\) = \(\frac { 4 }{ 3 }\)
Thus the required ratio = 4 : 3
b) Total number of students = 20 + 15 = 35
The ratio of number of girls to the total number of students = \(\frac { 20 }{ 35 }\) = \(\frac { 4 }{ 7 }\)
Thus the required ratio = 4 : 7.
Question 2.
Out of 30 students in a class, 6 like football, 12 like cricket and remaining like tennis. Find the ratio of
a) Number of students liking football to number of students liking tennis.
b) Number of students liking cricket to total number of students.
Solution:
Number of students in the class = 30
Number of students liking football = 6
Number of students liking cricket = 12
Number of students liking tennis = 30 – (6 + 12) = 30 – 18 = 12
a) Ratio of number of students liking football to the number of students liking tennis = \(\frac { 6 }{ 12 }\) = \(\frac { 1 }{ 2 }\)
Thus, the required ratio = 1 : 2.
b) The ratio of the number of students liking cricket to the total number of stdudents
= \(\frac { 12 }{ 30 }\) = \(\frac{12 \div 6}{30 \div 6}\) = \(\frac { 2 }{ 5 }\)
Thus, the required ratio = 2 : 5.
Question 3.
See the figure and find the ratio of
a) Number of triangles to the number of circles inside the rectangle.
b) Number of squares to all the figures inside the rectangle.
c) Number of circles to all the figures inside the rectangle.
Solution:
Number of triangles in the given diagram = 3
Number of circles in the given diagram = 2
Number of squares in the given diagram = 2
Total figures = 7
a) The ratio of number of triangles to the number of circles = \(\frac { 3 }{ 2 }\)
Thus, the required ratio = 3 : 2.
b) The ratio of number of squares to number of all figures =\(\frac { 2 }{ 7 }\)
Thus, the required ratio = 2 : 7.
c) The ratio of number of circles to the number of all the figures = \(\frac { 2 }{ 7 }\)
Thus, the required ratio = 2 : 7.
Question 4.
Distances travelled by Hamid and Akhtar in an hour are 9 km and 12 km. Find the ratio of speed of Hamid to the speed of Akhtar.
Solution:
Distance travelled by Hamid = 9 km
Distance travelled by Akhtar = 12 km
Speed of Hamid = 9 km per hour
Speed of Akhtar = 12 km per hour
∴ Ratio of the speed of Hamid to the speed of Akhtar = \(\frac { 9 }{ 12 }\) = \(\frac{9 \div 3}{12 \div 3}\) = \(\frac { 3 }{ 4 }\)
Thus, the required ratio = 3 : 4.
Question 5.
Fill in the following blanks :
Question 6.
Find the ratio of the following :
a) 81 to 108
Solution:
81 to 108 = \(\frac { 81 }{ 108 }\) = \(\frac{81 \div 9}{108 \div 9}\) = \(\frac{9 \div 3}{12 \div 3}\) = \(\frac { 3 }{ 4 }\)
Thus, the ratio = 3 : 4
b) 98 to 63
Solution:
98 to 63 = \(\frac { 98 }{ 63 }\) = \(\frac{98 \div 7}{63 \div 7}\) = \(\frac { 14 }{ 9 }\)
Thus, the ratio = 14 : 9
c) 33 km to 121 km
Solution:
33 km to 121 km = \(\frac { 33 km }{ 121 km }\) = \(\frac { 33 }{ 121 }\) = \(\frac{33 \div 11}{121 \div 11}\) = \(\frac { 3 }{ 11 }\)
Thus, the ratio = 3 : 11
d) 30 minutes to 45 minutes
Solution:
30 minutes to 45 minutes = \(\frac{30 \text { minutes }}{45 \text { minutes }}\) = \(\frac { 30 }{ 45 }\) = \(\frac{30 \div 15}{45 \div 15}\) = \(\frac { 2 }{ 3 }\)
Thus, the ratio = 2 : 3
Question 7.
Find the ratio of the following :
a) 30 minutes to 1.5 hours
Solution:
30 minutes to 1.5 hours
Ratio of 30 minutes to 1.5 hours = Ratio of 30 minutes to 90 minutes.
[ 1.5 hour = 1.5 × 60 minutes = 90 minutes] = \(\frac{30 \text { minutes }}{90 \text { minutes }}\)
= \(\frac { 30 }{ 90 }\) = \(\frac{30 \div 10}{90 \div 10}\) = \(\frac { 3 }{ 9 }\) = \(\frac{3 \div 3}{9\div 3}\) = \(\frac { 1 }{ 3 }\)
Thus, the ratio = 1 : 3.
b) 40 cm to 1.5 m
Solution:
40 cm to 1.5 m
1.5 m = 1.5 × 100 cm = 150 cm
∴ Ratio of 40 cm to 1.5 m
= Ratio of 40 cm to 150 cm
= \(\frac { 40 cm }{ 150 cm }\) = \(\frac { 40 }{ 150 }\) = \(\frac{40 \div 10}{150 \div 10}\) = \(\frac { 4 }{ 15 }\)
Thus, the ratio = 4 : 15.
c) 55 paise to ₹ 1
Solution:
55 paise to ₹ 1 = ₹ 1 = 100 paise
∴ Ratio of 55 paise to ₹ 1
= Ratio of 55 paise to 100 paise
= \(\frac { 55 paise }{ 100 paise }\) = \(\frac { 55 }{ 100 }\) = \(\frac{55 \div 5}{100 \div 5}\) = \(\frac { 11 }{ 20 }\)
Thus, the ratio = 11 : 20
d) 500 ml to 2 litres
Solution:
500 ml to 2 litres = 2 litres = 2 × 1000 ml = 2000 ml.
∴ Ratio of 500 ml to 2 litres
= 500 ml to 2000 ml
= \(\frac { 500 }{ 2000 }\) = \(\frac{500 \div 500}{2000 \div 500}\) = \(\frac { 1 }{ 4 }\)
Thus, the ratio = 1 : 4
Question 8.
In a year, Seema earns ₹ 1,50,000$ and saves ₹ 50,000. Find the ratio of
a) Money that Seema earns to the money she saves.
Solution:
Money earned by Seema = ₹ 1,50,000
Money saved by her = ₹ 50,000
Money spent by her = ₹ 1,50,000 – ₹ 50,000 = ₹ 1,00,000
∴ Ratio of money earned by Seema to the money saved by her
b) Money that she saves to the money she spends.
Sol. Money saved by Seema = ₹ 50,000
Money spent by Seema = ₹ 1,00,000
∴ Ratio of money saved and money spent by Seema
Question 9.
There are 102 teachers in a school of 3300 students. Find the ratio of the number of teachers to the number of students.
Solution:
Number of teachers = 102
Number of students = 3300
∴ Ratio of teachers to the students = \(\frac { 102 }{ 3300 }\) = \(\frac{102 \div 2}{3300 \div 2}\) = \(\frac{51 \div 3}{1650 \div 3}\) = \(\frac { 17 }{ 0550 }\)
Thus the ratio = 17 : 550.
Question 10.
In a college, out of 4320 students, 2300 are girls. Find the ratio of
a) Number of girls to the total number of students.
Solution:
Total number of students = 4320
Number of girls = 2300
∴ Number of boys = 4320 – 2300 = 2020
Ratio of number of girls to the total number of students
\(\frac { 2300 }{ 4320 }\) = \(\frac{2300 \div 10}{4320 \div 10}\) = \(\frac{230 \div 2}{432 \div 2}\) = \(\frac { 115 }{ 216 }\)
Thus, the ratio = 115 : 216.
b) Number of boys to the number of girls.
Solution:
Ratio of number of boys to the number of girls = \(\frac { 2020 }{ 2300 }\) = \(\frac{2020 \div 10}{2300 \div 10}\) = \(\frac{202 \div 2}{230 \div 2}\) = \(\frac { 101 }{ 115 }\)
Thus, the ratio = 101 : 115
c) Number of boys to the total number of students.
Solution:
Ratio of number of boys to the total number of students
= \(\frac { 2020 }{ 4320 }\) = \(\frac{2020 \div 10}{4320 \div 10}\) = \(\frac{202 \div 2}{432 \div 2}\) = \(\frac { 101 }{ 216 }\)
Thus, the ratio = 101 : 216
Question 11.
Out of 1800 students in a school, 750 opted basketball, 800 opted cricket and remaining opted table tennis. If a student can opt only one game, find the ratio of
a) Number of students who opted basketball to the number of students who opted table tennis.
Solution:
Total number of students = 1800
Number of students opted basket ball = -750
Number of students opted cricket = 800
Number of remaining students who opted table tennis = 1800 – (750 + 800) = 1800 – 1550 = 250
a) Ratio of number of students opted basket ball to the number of students who opted table tennis
= \(\frac{750 \div 10}{250 \div 10}\) = \(\frac{75 \div 25}{25 \div 25}\) = \(\frac { 3 }{ 1 }\)
Thus, the ratio = 3 : 1.
b) Number of students who opted cricket to the number of students opting basketball.
Solution:
Ratio of the students who opted cricket to the number of students opting basket ball
= \(\frac { 800 }{ 750 }\) = \(\frac{800 \div 10}{750 \div 10}\) = \(\frac{80 \div 5}{75 \div 5}\) = \(\frac { 16 }{ 15 }\)
Thus, the ratio = 16 : 15.
c) Number of students who opted basketball to the total number of students.
Solution:
Ratio of number of students who opted basket ball to the total number of students = \(\frac { 750 }{ 1800 }\) = \(\frac{750 \div 10}{1800 \div 10}\) = \(\frac{75 \div 5}{180 \div 5}\) = \(\frac{15 \div 3}{36 \div 3}\) = \(\frac { 5 }{ 12 }\)
Thus, the ratio = 5 : 12.
Question 12.
Cost of a dozen pens is ₹ 180 and cost of 8 ball pens is ₹ 56. Find the ratio of the cost of a pen to the cost of a ball pen.
Solution:
Cost of 1 dozen pens = ₹ 180 [1 dozen = 12 objects]
So, 12 pens cost = ₹ 180
∴ Cost of 1 pen = \(\frac { ₹ 180 }{ 12 }\) = ₹ 15
Cost of 8 ballpens = ₹ 56
∴ Cost of 1 ballpen = \(\frac { ₹ 56 }{ 8 }\) = ₹ 7
Now, the ratio of cost of 1 pen to cost of 1 ballpen = \(\frac { 15 }{ 7 }\) = 15 : 7
Thus required ratio = 15 : 7
Question 13.
Consider the statement: Ratio of breadth and length of a hall is 2 : 5. Complete the following table that shows some possible breadths and lengths of the hall.
Question 14.
Divide 20 pens between Sheela and Sangeeta in the ratio of 3 : 2.
Solution:
Total number of pens = 20
Dividing ratio = 3 : 2
We have 3 + 2 = 5
Thus, Sheela gets 12 pens and Sangeeta gets 8 pens
(OR)
Total number of pens = 20
Dividing ratio = 3 : 2
Let the number of pens Sheela gets = 3x pens
and Sangeeta gets = 2x pens
Total number of pens 3x + 2x = 20 = 5x = 20
x = \(\frac { 20 }{ 5 }\) = 4
∴ Number of pens Sheela gets = 3x = 3(4) = 12
Number of pens Sangeeta gets = 2x = 2(4) = 8
(OR)
So, Sheela gets 12 pens and Sangeeta gets 8 pens.
Question 15.
Mother wants to divide ₹ 36 between her daughters Shreya and Bhoomika in the ratio of their ages. If age of Shreya is 15 years and age of Bhoomika is 12 years, find how much Shreya and Bhoomika will get.
Solution:
Given that total dividing amount = ₹36
Dividing ratio
Money got by Shreya : Money got by Bhoomika = Shreya’s age: Bhoomika age
= 15: 12 = 5 : 4 [\(\frac { 15 }{ 12 }\) = \(\frac{15 \div 3}{12 \div 3}\) = \(\frac { 5 }{ 4 }\)]
Sum = 5 + 4 = 9
(or)
Bhoomika’s share = Total – Shreya’s share = ₹ 36 – ₹ 20 = ₹ 16
Question 16.
Present age of father is 42 years and that of his son is 14 years. Find the ratio of
a) Present age of father to the present age of son.
b) Age of the father to the age of son, when son was 12 years old.
c) Age of father after 10 years to the age of son after 10 years.
d) Age of father to the age of son when father was 30 years old.
Solution:
Present age of father = 42 years
Present age of his son = 14 years
a) Ratio of present age of father to the present age of son
\(\frac { 42 }{ 14 }\) = \(\frac{42 \div 2}{14 \div 2}\) = \(\frac{21 \div 7}{7 \div 7}\) = \(\frac { 3 }{ 1 }\)
Thus, the ratio = 3 : 1
b) When son was 12 years old, Le. 14 – 12 – 2 years ago father’s age = 42 – 2 = 40 years
Now the ratio of the father’s age to son’s age = \(\frac { 40 }{ 12 }\) = \(\frac{40 \div 4}{12 \div 4}\) = \(\frac { 10 }{ 3 }\)
Thus, the ratio = 10 : 3.
c) Age of father after 10 years = 42 + 10 = 52 years
Age of son after 10 years = 14 + 10 = 24 years
Now, ratio of father’s age after 10 years to the age of son after 10 years
= \(\frac { 52 }{ 24 }\) = \(\frac{52 \div 2}{24 \div 2}\) = \(\frac{26 \div 2}{12 \div 2}\) = \(\frac { 13 }{ 6 }\)
Thus, the ratio = 13 : 6.
d) When the father’s age is 30 years, i.e 42 – 30 = 12 ago son age = 14 – 12 = 2 years
Now the ratio of age of father to the age of son when father was 30 years
= \(\frac { 30 }{ 2 }\) = \(\frac{30 \div 2}{2 \div 2}\) = \(\frac { 15 }{ 1 }\)
Thus, the ratio = 15 : 1.