Question

Keisha is working on a math worksheet with 50 problems. She has completed 20 problems in 25 minutes. If she continues at the same pace, what will the total time be for her to complete the worksheet? A) 31.25 minutes B) 62.5 minutes C) 70 minutes D) 75 minutes Elim

Answer 1

You first divide 25 by 20 = 25/20= 1.25 That means it takes her 1 minute and 25 seconds to do one question. (unit rate) Then you multiply 1.25 by 50 which equals 62.5 so it'll take her 62 minutes and 30 seconds so B is your answer :)

Answer 2

Keisha's work rate is 20 problems / 25 minutes, or (4/5) problem/ minute.

She has 30 more problems to do.  How long will this take?  

30 problems
------------------------------- = 37.5 minutes 
(4/5) problem / minute

You must add this "37.5 minutes" to the original "25 minutes."  

The end result is 62.5 minutes (answer)