Question

In a school, 3/5 of the children are boys and the
number of girls is 800. Then the number of boys are
(A) 800
B) 1000
(C) 1200
(D) 2000​

Answer 1

Answer:

1200

Step-by-step explanation:

If 3/5 are boys, then 2/5 are girls

2/5 x = 800

2x = 4000

X = 2000

3/5x = 3/5×2000

1200

Then number of boys are 1200

Answer 2

Given: Number of female students in a school = 800

           Number of male students in the school = $\frac{3}{5}$ of total students

To find: Number of boys

Let: Total number of students be $x$

Solution: According to the given question and assumption made,

If number of male students = $\frac{3}{5}$ of total students then, number of female students should be  $\frac{2}{5}$ of total students.

So, $\frac{2}{5}$ × $x$ = 800

⇒ $2x = 800$ × $5$ $= 4000$

⇒ $x = \frac{4000}{2} = 2000$

Total number of students in the school = $2000$

Number of male students = Total number of students - Number of female students

                           = $2000 - 800 = 1200$

Hence, the number of boys are 1200.