Question

Jill arranges quarters in stacks of increasing powers of 2,starting with the zeroth power (2^0).If she ends up with six stacks,how man coins has she used?

Answer 1

2⁰ = 1
2¹ = 2
2² = 4
2³ = 8
2⁴ = 16
2⁵ = 32

The sum = (the next power of 2) - 1

2⁶ - 1 = 63 .

($15.75 if she's stacking quarters)