% Word Problem has me stumped

Aug 2019
2
0
US
Rob spent 25% more time on his project than he had planned. He spent an extra "h" hours on it.

Which of the following expressions could represent the number of hours Rob actually spent on the project:

A: 5 h

B: (h/25) 1.25

C: 1.25 h

D: 4 h

E: (1+ 25/100) h

In the solution they set up the answer by starting with h/.25

Why would we need to calculate what 25% of "h" which is the extra time spent? It makes no sense to determine what 25% of the extra time is since "h" IS the extra time spent.

Any help would be greatly appreciated since I'm at a loss here. (Doh)
 
Jun 2013
1,144
612
Lebanon
In the solution they set up the answer by starting with h/.25

Why would we need to calculate what 25% of "h" which is the extra time spent? It makes no sense to determine what 25% of the extra time is since "h" IS the extra time spent.

Any help would be greatly appreciated since I'm at a loss here. (Doh)
that is not \(\displaystyle 25\)% of \(\displaystyle h\)

\(\displaystyle 25\)% of $h$ would be \(\displaystyle .25h\)
 
Aug 2019
2
0
US
I still don't see what they're are doing here.

They really should explain it once, which they have not done. They just lay it out. That's teaching? Explain it at least once. That's teaching.
 
Last edited:
Jun 2013
1,144
612
Lebanon
I would set it up like this

project planned time: \(\displaystyle t\)

extra time: \(\displaystyle h\)

total time spent on project: \(\displaystyle t + h\)

Given \(\displaystyle h=0.25t\) find \(\displaystyle t+h\)
 
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