Re: Working together, A and B can complete a work in 10 days, B and C can
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04 May 2023, 09:49
A's rate = 1/a
B's rate = 1/b
C's rate = 1/c
1/a + 1/b = 1/10
1/b + 1/c = 1/12
1/a + 1/c = 1/15
Add the three equations:
2/a + 2/b + 2/c) = 15/60
2(1/a + 1/b + 1/c) = 1/4
Since we need A, B, and C to be working together, we need to divide both sides by 2:
(1/a + 1/b + 1/c) = 1/8
Their combined rate is 1/8, which means that together they will spend 8 hours working.