Answer:
William can eat 18 slices of pizza in half of an hour.
William can eat a whole box of pizza in 20 minutes.
Explanation:
30 minutes in half of an hour, 30/5 is 6.
3 slices in 5 mins
3 times 6 is 18.
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3 slices ---> 12 slices
x4
5 mins---> 20 mins
x4