Question 428016
An experienced bricklayer can construct a small wall in 3 hours. An apprentice can complete the job in 7 hours. Find out how long it takes if they work together.

Let x be the time that both work together

Then bricklayer's rate is x/3
An apprentice's rate is x/7

To complete the job together :

x/3 + x/7 = 1

Multiply both sides by LCD (21)

7x + 3x = 21
10x = 21
x = 21/10

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