Thanks again for the time you've all spent helping me out.

]]>7 hours = 420 minutes

special questionaires = .2 q (q=any questionaire)

simple questionaires = .8 q

total time = .8q(10 minutes) + .2q(30 minutes)

420 = .8q(10) + .2q(30)

420 = q(8 + 6)

q = 420/14 = 30

The average concept used by mathsyperson never even occured to me. Go figure.

]]>He has 30 questionnaires. 24 (ie 80%) take 10 mins, and 6 (ie 20%) take 30 mins. 24×10 + 6×30 = 420 mins = 7 hrs.

]]>80% of them are short and he takes 10 minutes, so we do 80%/100% * 10 minutes = 8 minutes.

The other 20% are long and take 30 minutes, so we do 20%/100% * 30 minutes = 6 minutes.

Add these to get the total average time and we get 14 minutes.

He works for 7 hours, which is 420 minutes.

Therefore, he can deal with 420/14 = 30 questionnaires in 1 day.

]]>I have a mathematical problemt hat I just can't work out so I figured I'd put out there and see if anyone can help. I need a formula for the following situation:

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Bob works 7 hours a day dealing with completed questionnaires posted to him.

Most questionnaires are easy to deal with and take him 10 minutes to deal with.

But if a questionnaire needs special attention it takes Bob 30 minutes to deal with it.

Assuming that only 20% of questionnaires need special attention, how many questionnaires can Bob deal with on 1 day?

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My brain cannot deal with this problem, but I'm hoping I have provided all the neccessary information for a solution. Never was any good with percentages.

Hope someone has fun working it out or can point me in the right direction!

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