Question

You leave a pile of sand in your backyard on a windy day. Every minute the wind blows away 10 percent of the remaining sand. You started with five cubic feet of sand. What equation models the amount of sand after minutes?

Answer 1

the RIGHT answer is y = 5 x 0.90^x

Explanation:

ten percent has already been blown away, so you only include the percentage of what hasn't been blown away in the equation. (also i just did the assignment and got 100% so you can trust this).

Answer 2

1. 10% of the remaining sand
2. You had 5 ft of sand
3. So y=5(.10(x))