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The Problem

A mad scientist develops a formula which can turn a light bulb into a camel. Working alone, it takes the scientist 4 hours to create one dose of formula. The mad scientist's slightly mad assistant Igor can make one dose in 12 hours. How long, working together, will it take the mad scientist and Igor to create one dose of formula? Answer the question by using a table and the 5-step method.

Answer provided by our tutors

Scientist DATA:

time = 4 hr/job ; rate = 1/4 job/hr

Igor DATA:

time = 12 hr/job ; rate = 1/12 job/hr

Together DATA:

time = x hr/job ; rate = 1/x job/hr

Equation:

rate + rate = together rate

1/4 + 1/12 = 1/x

Multiply thru by 12x to get:

3x + x = 12

4x = 12

x = 3 hr (time required for them to do the job together

 

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