Wofford09 wrote:

reto wrote:

Brian has to clean 675 beer glasses. If he cleans 16% of the glasses in the first 88 minutes, then which of the following is closest to the number of hours Brian has to work at double his initial speed, to finish cleaning the rest of the glasses?

A. 4.1

B. 7.8

C. 8

D. 8.2

E. 3.9

is this really a sub 600? I got it right but the calculations took me just over 3 mins. The process is very simple, but the numbers are not the best.

Im actually not sure what level it is because it was not stated. I would try like that:

Brian's rate of cleaning glasses is \(=\frac{0.16*675}{88}\) glasses/minute

For the remaining glasses he has the double rate: \(2 * \frac{0.16*675}{88}\)

Now all you have to do is divide the remaining classes through the new double rate (don't calculate the exact number but use 0.84*675 for the remaining glasses) like that:

\(\frac{0.84*675*88}{2*0.16*675}\)

Then cancel out as much terms as possible (675 cancels, 88 cancels with the 2 in the denominator and 0.84 divided with 0.16 is approx 5 times). This leaves you with a nice approximation of 5*44 minutes = 220min = 3.6 hours. I think that should be enough.

If you want to be more precise look at the solution from

EgmatQuantExpert and do it with the whole percent numbers.

Does this help?

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