Question

The number of lava cakes on display at a cafe was 3/4 of the number of cupcakes on display. After 20 lava cakes were bought and the staff added another 30 cupcakes, the number of cupcakes was twice the number of lava cakes. The last group of customers bought 5 cupcakes each, finishing all the cupcakes on display. How many customers were there in the last group?

Answer 1

if the cupcake is 20, lava cake is 3/4x
2(3/4x - 20) = 70 + 30
3/2x - 40 = x + 30
1/2x = 70
x = 140
140 + 30 = 170
170 ÷ 5
= 34