Question

In a particular schod, out of total 640 boy that
include all the age group, 60% of boys below.
18 were enrolled outof them 50% attended
school irregularly. In 120 among them were regula
in school, how many boys were there in
school who are above 18?​

Answer 1

Answer:

The number of boys were there in school above 18 is 240 .

Step-by-step explanation:

Given as :

Total numbers of boys of all age group = 640

60% of boys below 18 were enrolled

The number of boys were regular = 120

Let The number of boys were there in school above 18 =  640 - x

Let The total number of boys below 18 years = 100

∵ 60% of boys below 18 were enrolled

So, 60 % of 100 = $\dfrac{60}{100}$  × 100

i.e 60 % of 100 =  60

Again

50 % of them attend school irregularly

So, $\dfrac{50}{100}$ × 60

Or, 5 × 6 = 30

So, number of boys who attend school irregularly = 30

Again

So, number of boys who attend school regularly = 60 - 30 = 30

Now, putting the value in proportion .

30 : 100 : : 120 : x

Or, $\dfrac{30}{100}$   =  $\dfrac{120}{x}$

Or, x = $\dfrac{120\times 100}{30}$

Or, x = 400

So, The number of boys were there in school above 18 =  640 - x

Or, The number of boys were there in school above 18 =  640 - 400 = 240

Hence, The number of boys were there in school above 18 is 240 . Answer