280 mangoes are divided among some boys and girls whose total number is 50 so that each boy gets 5 mangoes and each girl get 7 mangoes. The number of girls is

15

According to the question:

B + G = 50 ----(i)

5B + 7G = 280 ----(ii)

Multiplying 1 equation by 5 so we get:

5B + 5G = 250 -----(iii)

5B + 7G = 280 ------(iv)

Subtracting (iii) from (iv)

5B + 7G - 5B - 5G = 280 - 250

2G = 30

G = 15