Answer:
120 gumballs
Step-by-step explanation:
Let
x = total gumballs
Buddy = 1/2x
Balance = x - 1/2x
= 2x-x/2
= 1/2x
Miranda = 1/2 of 1/2x
= 1/2 × 1/2x
= 1/4x
Balance = 1/2x - 1/4x
= 2x-x/4
= 1/4x
Zack = 1/2 of 1/4x
= 1/2 × 1/4x
= 1/8x
Balance = 1/4x - 1/8x
= 2x-x/8
= 1/8x
His sister = 5
Balance = 1/8x -5
10 = 1/8x - 5
10 + 5 = 1/8x
15 = 1/8x
x = 15 ÷ 1/8
= 15 × 8/1
= 120
x = 120 gumballs