# Chapter 9: Ratio, Proportion and Unitary Method Exercise 9.4

## Ratio, Proportion and Unitary Method – Exercise 9.4 – Q.1

The price of 3 meters of cloth = Rs 79.50

Let the price of 15m cloth be x

Then,

By cross multiplication, we get

⟹ x = 5 × 79.50

⟹ x = Rs 397.50

## Ratio, Proportion and Unitary Method – Exercise 9.4 – Q.2

Cost of 17 chairs = Rs 9605

Number of chairs purchased

= 100 chairs.

## Ratio, Proportion and Unitary Method – Exercise 9.4 – Q.3

Three ferry loads carry  = 150 people

one ferry load carry = 150/3 people

= 50 people

Number of peoples  can be carried by 4 ferryloads = 50 × 4

= 200 people.

## Ratio, Proportion and Unitary Method – Exercise 9.4 – Q.4

9 kg rice cost 120.60

50 kg cost = ?

1 kg rice cost = 120.60/9

= 13.4

50 kg rice cost = 13.4 × 50

= 670

∴ 50 kg rice cost = Rs. 670

## Ratio, Proportion and Unitary Method – Exercise 9.4 – Q.5

Train runs 200 km in 5 hours.

Train runs in one hour = 200/5 km

= 40 km

∴  No of Kms does it run in 7 hrs = 7 × 40 km

= 280 km

## Ratio, Proportion and Unitary Method – Exercise 9.4 – Q.6

10 boys can dig a pitch in 12 hours.

8 boys can dig pitch in x hrs

one boy can dig pitch in = 12 × 10 = 120 hrs

8 boys can dig pitch in = 120/8

= 15 hrs.

## Ratio, Proportion and Unitary Method – Exercise 9.4 – Q.7

Daily 8 hours → work finishes in 72 days.

6 hrs daily → ?

Daily one hour = 12 × 8 = 96 days

No of day will take 6 hrs daily works = 96/6 = 16 days.