Problem Set 3: Rates and Conversion

Question

4. Jamie made 7 paper airplanes in 2 minutes. She wants to make 10 paper airplanes. If Jamie works at the same rate, which of the following proportions can be used to determine x, the number of minutes airplanes?

A. 1 10 = x 2 + 7 B. 10 1 = x 2 + 7 C. 7 2 = 10 x D. 2 7 = 10 x

Answer 1

Hello, Wary,

Perhaps there are some typos in your answer options - I didn't see one that matches the question.

Jamie's rate is 7 planes in 2 minutes, or 3.5 planes/minute.

The equation is thus Y(planes) = 3.5 planes/min * X (minutes)

Using 10 for Y, we get X = 2.857 minutes, ignoring sig figs.

Bob

As written, the answer options don't make sense to me:

A. 1 10 = x 2 + 7 : what is 1 10? At any rate, this says he will have 7 planes before he even starts (X = 0)

B. 10 1 = x 2 + 7 : 10 1? This also claims he gets 7 planes before starting

C. 7 2 = 10 x : 7 2?

D. 2 7 = 10 x : 2 7?

Neither of the last two make sense. The 10X factor suggests he is making planes at 10/minute.