Question

Pipe A can fill 3 tanks in 8 minutes. Pipe B can fill 5 tanks in 10 minutes. How long will it take for them to fill a single tank if they work together?

Answer 1

c =4 4/9 minutes

Explanation:

The formula is

1/a + 1/b = 1/c where a and b is the time for each working alone and c is the time working together

1/8 + 1/10 = 1/c

Multiply by 40c to clear the fractions ( 40c is the least common multiple)

40c(1/8 + 1/10 = 1/c)

5c + 4c = 40)

9c = 40

Divide by 9

9c/9 = 40/9

c =4 4/9 minutes