**Question 1:** The strength of a school increases and decreases in every alternate year by 10%. It started with increase in 2000. Then, the strength of the school in 2003 as compared to that in 2000 was

(a) increased by 8.9%

(b) decreased by 8.9%

(c) increased by 9.8%

(d) decreased by 9.8%

### Answers and Explanations

**Answer 1: a **

Let the strength of school in 2000 is 100.

According to question, in year 2001 strength increased by 10%

So, new strength = {100 x (100 + 10)/100} = 110

In year 2002, strength decreased by 10%

So, new strength ={100 x (100 – 10)/100} = 99

Again in year 2003, it increased by 10%

So, new strength = {99 x (100 + 10)/100} = 108.9

Percentage Change = {(108.9 – 100)/100} x 100 = 8.9%

The strength in 2003 as compared to 2000 is increased by 8.9%.

**Question 2:** A number is increased by 10% and then the increased number is decreased by 10%. The net increase or decrease is

(a) increased by 2%

(b) decreased by 1%

(c) increased by 10%

(d) decreased by 10%

### Answers and Explanations

**Answers: (b)**

Percentage change formula when a number is first increased by x% and then decreased by y%

{x – y – (xy/100)}%

Here, x = 10% and y = 10%

Percentage change= {10 – 10 – (10 x 10)/100} = -1%

Thus, there is 1% decrease.

**Question 3:** During the first year the population of a village is increased by 5% and the second year it is diminished by 5%. At the end of the second year its population was 47880. What was the population at the beginning of the first year?

(a) 45500

(b) 48000

(c) 43500

(d) 53000

### Answers and Explanations

**Question 4: ** When the price of article was reduced by 20% its sale increased by 80%. What was the net effect on the revenue?

(a) 44% increase

(b) 44% decrease

(c) 66% increase

(d) 75% increase

### Answers and Explanations

**Question 5:** Two successive price increases of 10% and 10% of an article are equivalent to a single price increase of

(a) 19%

(b) 20%

(c) 21%

(d) 22%

### Answers and Explanations

### Percentages: The Complete Lesson

#### Table of Contents

**Concept Articles**

**Exercises**

**Tests**