Question

15. A number exceeds 20% of itself by 40. The number is
(a) 50
(b) 60
(c) 80
(d) 320

16. A number decreased by 27 whole 1/2% gives 87. The number is
(a) 58
(b) 110
(c) 120
(d) 135

17. 0.05 is what per cent of 20?
(a) 25%
(b) 2.5%
(c) 0.25%
d 0.025%

18. One-third of 1206 is what per cent of 134?
(a) 3%
(b) 30%
(c) 20%
d 300%
​

Answer 1

Answer:

Answer :-

1Q

(a)50

Explanation :-

Given :

A number exceeds 20% of itself by 40

To find :

The number

Solution :

Let the number be x

According to question,

= > x - 20\% \: of \: x = 40=>x−20%ofx=40

= > x - \dfrac{20}{100} \times x = 40=>x−

100

20

×x=40

= > x - \dfrac{20x}{100} = 40=>x−

100

20x

=40

= > x - \dfrac{x}{5} = 40=>x−

5

x

=40

= > \dfrac{5x - x}{5} = 40=>

5

5x−x

=40

= > \dfrac{4x}{5} = 40=>

5

4x

=40

= > 4x = 200=>4x=200

= > x = \dfrac{200}{4}=>x=

4

200

= > x = 50=>x=50

Hence, the number is 50.

Verification :-

Putting the value of x

= > 50 - 20\% \: of \: 50 \: = 40=>50−20%of50=40

= > 50 - \dfrac{20}{100} \times 50 = 40=>50−

100

20

×50=40

= > 50 - 10 = 40=>50−10=40

= > 40 = 40=>40=40

Therefore, L.H.S = R.H.S

Hence, Proved.