effatara wrote:
A chef can bake a certain number of cakes in a given amount of time. In twice that time, an assistant can bake thrice the number of pies as the chef can bake cakes in the given amount of time. For both the chef and the assistant, working at their respective efficiencies, it takes twice as long to bake a cake than it does a pie. If, together, they can bake 20 cakes and 30 pies in 4 hours, how many pies can the chef alone bake in an hour?
(A) 12
(B) 15
(C) 7.5
(D) 10
(E) 12.5
If a cake takes twice as long as a pie, then each cake is like 2 pies. So they can make 70 pies together in 4 hours.
The second sentence of the question isn't in English, but I think they mean to say that the number of pies the assistant can make in 2 hours is 3 times the number of cakes the chef can make in 1 hour. If c is the number of cakes the chef makes in an hour, then 2c is the number the chef makes in 2 hours, and since a cake is like 2 pies, the chef makes 4p pies in 2 hours. The assistant makes 3p pies in 2 hours. So in a fixed amount of time, the work done by the chef and by the assistant is in a 4 to 3 ratio, and if they can make 70 pies in 4 hours together, the chef must be making 40 of those pies, and thus makes 10 pies per hour.
The question is not well-written - what is the source?
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