# Exercise 9.3

## 1. Which of the following are in proportion?

### (i) 33, 44, 66, 88

#### Solution:

We have, ∴ 33 : 44 = 66: 88

Thus, 33: 44, 66, 88 are in pro proportion

### (ii) 46, 69, 69, 46

#### Solution:

We have: ∴  46: 69 ≠ 69: 46

Thus, 46, 69, 69, 46 are not in proportion.

### (iii) 72, 84, 186, 217

#### Solution:

We have,

72, 84, 184, 217 Thus, 72, 84, 186, 217 are in proportion.

## 2. Find x in the following proportions

### (i) 16:1= x:96

#### Solution: ### (ii) x:92 = 87 : 116

#### Solution: ### 3. The ratio of income to the expenditure of a family is 7: 6. Find the savings if the income is Rs.1400.

#### Solution:

The ratio of income and expenditure = 7: 6

7x = 1400

x = 200

Expenditure = 6x = 6 × 200

= Rs.1200

Savings = Income – Expenditure

= 1400 -1200

= Rs.200

### 4. The scale of a map is 1: 4000000. What is the actual distance between the two towns if they are 5cm apart on the map?

#### Solution:

The scale of map = 1: 4000000

Let us assume the actual distance between towns is x cm

1: 4000000 =5: x

x = 5 × 4000000

= 20000000 cm

1km = 1000 m

1m = 100 cm

Therefore, x = 200 km

### 5. The ratio of income of a person to his savings is 10: 1. If his savings for one year is Rs.6000, what is his income per month?

#### Solution:

Given that the ratio of income of a person to his savings is 10:1

Savings per year = 6000

Savings per month = 6000/12

= Rs. 500

Than let income per month be x

X: 5000 = 10: 1

X = 500×10

X = 5000

Income per month is Rs. 5000

### 6. An electric pole casts a shadow of length 20 metres at a time when a tree 6 metres high casts a shadow of length 8 metres. Find the height of the pole.

#### Solution:

Height of the tree: Length of the shadow of tree

Height of the pole: Length of the shadow of pole

x: 20 = 6: 8

x = 120/8

x = 15

Updated: December 18, 2019 — 3:14 pm