NCERT Solutions Class 6th Maths Chapter – 12 Ratio and Proportion Exercise – 12.3

Question 1. If the cost of 7 m of cloth is ₹ 1470, find the cost of 5 m of cloth.

Solution –

Given,
Cost of 7 m cloth = ₹ 1470
Cost of 1 m cloth = 1470 / 7
= ₹ 210
So, cost of 5 cloth = 210 × 5 = 1050
∴ Cost of 5 m cloth is ₹ 1050

Question 2. Ekta earns ₹ 3000 in 10 days. How much she will earn in 30 days?

Solution –

Money earned by Ekta in 10 days = ₹ 3000
Money earned in one day by her = 3000 / 10
= ₹ 300
So, money earned by her in 30 days = 300 × 30
= ₹ 9000

Question 3. If it has rained 276 mm in the last 3 days, how many centimeters of rain will fall in one full week (7 days)? Assume that the rain continues to fall at the same rate.

Solution –

Measure of rain in 3 days = 276 mm
Measure of rain in one day = 276 / 3
= 92 mm
So, measure of rain in one week i.e 7 days = 92 × 7
= 644 mm
= 644 / 10
= 64.4 cm

Question 4. Cost of 5 kg of wheat is ₹ 91.50.

(A) What will be the cost of 8 kg of wheat?

(B) What quantity of wheat can be purchased in ₹ 183?

Solution – 

(A) Cost of 5 kg wheat = ₹ 91.50.
Cost of 1 kg wheat = 91.50 / 5
= ₹ 18.3
So, cost of 8 kg wheat = 18.3 × 8
= ₹ 146.40

(B) Wheat purchased in ₹ 91.50 = 5 kg
Wheat purchased in ₹ 1 = 5 / 91.50 kg
So, wheat purchased in ₹ 183 = (5 / 91.50) × 183
= 10 kg

Question 5. The temperature dropped 15 degree Celsius in the last 30 days. If the rate of temperature drop remains the same, how many degrees will the temperature drop in the next ten days?

Solution –

Temperature drop in 30 days = 15o C
Temperature drop in 1 day = 15 / 30
= (1 / 2)o C
So, temperature drop in next 10 days = (1 / 2) × 10
= 5o C
∴ The temperature drop in the next 10 days will be 5o C

Question 6. Shaina pays ₹ 15000 as rent for 3 months. How much does she has to pay for a whole year, if the rent per month remains same?

Solution –

Rent paid by Shaina in 3 months = ₹ 15000
Rent for 1 month = 15000 / 3
= ₹ 5000
So, rent for 12 months i.e 1 year = 5000 × 12
= ₹ 60,000
∴ Rent paid by Shaina in 1 year is ₹ 60,000

Question 7. Cost of 4 dozen bananas is ₹ 180. How many bananas can be purchased for ₹ 90?

Solution –

Number of bananas bought in₹ 180 = 4 dozens
= 4 × 12
= 48 bananas
Number of bananas bought in ₹ 1 = 48 / 180
So, number of bananas bought in ₹ 90 = (48 / 180) × 90
= 24 bananas
∴ 24 bananas can be purchased in ₹ 90

Question 8. The weight of 72 books is 9 kg. What is the weight of 40 such books?

Solution –

Weight of 72 books = 9 kg
Weight of 1 book = 9 / 72
= 1 / 8 kg
So, weight of 40 books = (1 / 8) × 40
= 5 kg
∴ Weight of 40 books is 5 kg

Question 9. A truck requires 108 litres of diesel for covering a distance of 594 km. How much diesel will be required by the truck to cover a distance of 1650 km?

Solution –

Diesel required for 594 km = 108 litres
Diesel required for 1 km = 108 / 594
= 2 / 11 litre
So, diesel required for 1650 km = (2 / 11) × 1650
= 300 litres
∴ Diesel required by the truck to cover a distance of 1650 km is 300 litres

Question 10. Raju purchases 10 pens for ₹150 and Manish buys 7 pens for ₹ 84. Can you say who got the pens cheaper?

Solution –

Pens purchased by Raju in ₹ 150 = 10 pens
Cost of 1 pen = 150 / 10
= ₹ 15
Pens purchased by Manish in ₹ 84 = 7 pens
Cost of 1 pen = 84 / 7
= ₹ 12
∴ Pens purchased by Manish are cheaper than Raju.

Question 11. Anish made 42 runs in 6 overs and Anup made 63 runs in 7 overs. Who made more runs per over?

Solution –

Number of runs made by Anish in 6 overs = 42
Number of runs made by him in 1 over = 426 = 7 runs.
Number of runs made by Anup in 7 overs = 63
Number of runs made by him in 1 over = 637 = 9 runs.
∴ 9 runs > 7 runs.
Thus, Anup has made more runs.