Question

If it takes Zoe 5 minutes to polish 3 pieces of silverware, then at that rate, how many pieces of silverware can she polish in an hour and a half? Show or explain how you got your answer

Answer 1

All this problem is, is simply a proportion type of problem. So make the known proportion or the rate that you know like this :

5 min/3 pieces

Then convert 1 and 1/2 hr into minutes :
1 hr = 60 min
1/2 hr = 30 min
1 1/2 hr = 90 min

So if she takes 5 min to polish 3 pieces of silverware, how much silverware can she polish in 90 minutes.

5 min/3 pieces
90 min/ ? pieces.

Cross multiply the fractions

3 • 90 = 5 • ?
270 = 5?
270/5 = 5?/5
54 = ?

She can polish 54 pieces of silverware in an hour and half or 90 minutes.

Answer 2

Since it takes her 5 minuets to polish 3 pieces, then for an hour and a half (90 minuets) she will polish 54 pieces.
WORK:
90/5 = 18
18x3 = 54 pieces