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2007 AIME II Problems/Problem 4

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Problems

The workers in a factory produce widgets and whoosits. For each product, production time is constant and identical for all workers, but not necessarily equal for the two products. In one hour, 100 workers can produce 300 widgets and 200 whoosits. In two hours, 60 workers can produce 240 widgets and 300 whoosits. In three hours, 50 workers can produce 150 widgets and m whoosits. Find \displaystyle m.

Solutions

Suppose that it takes x hours for one worker to create one widget, and y hours for one worker to create one whoosit.

Therefore, we can write that (note that two hours is similar to having twice the number of workers, and so on):

100 = 300x + 200y

2(60) = 240x + 300y

3(50) = 150x + my

Solve the system of equations with the first two equations to find that (x,y) = \left(\frac{1}{7}, \frac{2}{7}\right). Substitute this into the third equation to find that 1050 = 150 + 2m, so m = 450.

See also

2007 AIME II (ProblemsResources)
Preceded by
Problem 3
Followed by
Problem 5
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
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