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# What am I doing wrong? (silly maths error) watch

1. I'm a little tired and should probably just sleep it off but this is really bugging me. Something isn't right in my thinking here:

Sally studies for 5 ASs, for each subject she dedicates an hour a week per subject. Unfortunately, she flunks the summer exam for one of her subjects and so has to drop it the next year. However, she is only going to use the original 5 hours to study for the remaining 4 subjects. How much extra time does she have to dedicate to make sure she makes an offer?

Well, my first instinct was 1/5 because there's an hour freed up. So 20%.

but an hour is an extra 15mins/subject which = 25% increase.

I assumed that this just meant her overall time towards studying for those subjects increases by 20%, and that each subject gets an extra 25% time boost, but apparently this is incorrect.

What the hell voodoo maths am I doing here?
2. (Original post by hockham jaynsaw)
I'm a little tired and should probably just sleep it off but this is really bugging me. Something isn't right in my thinking here:

Sally studies for 5 ASs, for each subject she dedicates an hour a week per subject. Unfortunately, she flunks the summer exam for one of her subjects and so has to drop it the next year. However, she is only going to use the original 5 hours to study for the remaining 4 subjects. How much extra time does she have to dedicate to make sure she makes an offer?

Well, my first instinct was 1/5 because there's an hour freed up. So 20%.

but an hour is an extra 15mins/subject which = 25% increase.

I assumed that this just meant her overall time towards studying for those subjects increases by 20%, and that each subject gets an extra 25% time boost, but apparently this is incorrect.

What the hell voodoo maths am I doing here?
Is there more to the question? What determines whether she makes an offer or not?

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