Help!!

25/20 =1.25 -1 =.25 x 100 =25% more time spent on his HW.

25/20 =1.25 x 100 =125% He is right.

By saying "125% more time", he is saying that the extra time he spent was 125% of the orginal amount.

Last week he spent 20 hours. This week, he spent 25 hours, 5 more hours.

Comparing the extra hours (5) to the hours that he spent last week (20):  5/20  =  25% extra time.

The hours that he spent this week, when compared to the hours last week, is 125%; but this isn't 125% more time.  

I have puzzled over this question before.

He spent 125% of his time on homework compared to last week BUT I think that is 25% MORE than last week.