Correct Answer - Option 1 : 15
Let the number of boys be ‘x’ and number of girls be ‘y’.
So, total number of students in the class = x + y
If each boy gets 5 apples, then each girl will get 7 apples.
According to question:
5x + 7y = 85 ______ (i)
And, if each boy gets 4 apples, then each girl will get 9 apples.
4x + 9y = 85 ______ (ii)
Equating equation (i) and (ii), we get:
5x + 7y = 4x + 9y
⇒ 5x – 4x = 9y – 7y
⇒ x = 2y
Putting the value of ‘x’ in equation (i), we get:
5(2y) + 7y = 85
⇒ 10y + 7y = 85
⇒ 17y = 85
⇒ y = 85 ÷ 17
⇒ y = 5
As x = 2y and y = 5
The value of x = 2 × 5 = 10
Therefore, total number of students in the class = x + y = 10 + 5 = 15
Hence, ‘15’ is the correct answer.
