Answer:
Alex's rock
Step-by-step explanation:
Marianne's distance: 15 inches 4 times = 15 * 4 = 60 inches
we can convert Marianne's distance to feet so we can easily compare it to Alex's
12 inches = 1 foot
1 foot/12 inches = 1. We divide by inches and not feet so that the inches cancel out, as can be seen in the calculations below.
60 inches * 1 = 60 inches * 1 foot/12 inches = 5 feet
7 feet > 5 feet
Alex's rock skipped the furthest
