Marcus spent 10 hours doing his homework last week. this week he spent 11 hours doing homework. he says that he spent 110% more time doing homework this week. is he correct? show your work to justify your decision.

We know that Marcus spent 10 hours on his homework this week so:
10 hours = 100%

Marcus is saying that he spent 110% more time doing his homework this week, in comparison to last week.

Then to see if he is correct we have to find 110% of 10 hours.

So if: 100% of 10 hours = 10 hours
And: 10% of 10 hours (equivalent to 600 minutes) = 1 hour (or 60 minutes)
Then we add the two: 10 hours + 1 hour
And we get: 11 hours

As a result Marcus is correct; he did spend 110% more time on his homework this week.

Hope it helped :)