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%

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%

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 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 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% 