How many quarters and dimes are in 6 dollars?

If you want only quarters, divide 6 / 0.25. [24 quarters, 0 dimes]

If you want only dimes, divide 6 / 0.1. [60 dimes, 0 quarters]

If you want some combination of quarters and dimes, you can experiment a bit. For this specific problem, you'll need an even number of quarters to get the exact amount - so you can use zero quarters, 2 quarters, 4 quarters, etc.