SOLUTION: Inverse variation, Solve following problem 1. The time t required to do a job varies inversely as the number of people p working. It takes 5 hours for 7 bricklayers to complete

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Question 1175777: Inverse variation, Solve following problem
1. The time t required to do a job varies inversely as the number of people p working. It takes 5 hours for 7 bricklayers to complete a certain job. How long will it take for 10 bricklayers to complete the job?
Found 2 solutions by math_helper, Theo:
Answer by math_helper(2461) About Me  (Show Source):
You can put this solution on YOUR website!
Each bricklayer does 1/(5*7) = 1/35 job per hour (so one bricklayer would take 35hrs to do the job on their own)

Knowing this, 10 bricklayers can do 10/35 job per hour

Thus, the total time for 10 bricklayers to do 1 job is:
1/(10/35) = 35/10 = 3.5hrs

Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
inverse variation formula is t = k / p
when t = 5 and p = 7, formula becomes 5 = k / 7
solve for k to find k = 35.
that's your constant of variation.
it is solved for from the given values of t and p.
if you are given a new value to t, it is used to solve for p.
if you are given a new value to p, it is used to solve for t.
if you are given two new values for both t and p, then a new value of k is solved for.
in this problem you are given a new value for p and asked to solve for t.
when p = 10, formula becomes t = 35 / 10
solve for t to get t = 3.5
that's your answer.