Problema Solution

At the school disco, half of the pupils ate crisps, one third ate sweets, 15 pupils ate neither, and nobody ate both.

How many pupils were there at the disco?

Answer provided by our tutors

let no. of pupil at disco be x

as given 

x - x/2 -x/3 = 15

(6x-3x-2x)/6 = 15

 x = 15*6 =90

total no. of pupil in disco = 90