A and B together can do a work in 6 days. If A alone can do it in 15 days. In how many days can B alone do it.

10 days to complete

Step-by-step explanation:

for mixed rate problems, the sum of each individual reciprocal rates equals the sum of the combined rate

i.e

we are given,

A's rate = 15 days to complete

Combined rate = 6 days to complete

B's rate = need to find

substituting' the given info into the equation above,

1/15 + 1/ (B's Rate) = 1/6

1 / (B's Rate) = 1/6 - 1/15  (convert right side to same denominator)

1 / (B's Rate) = 5/30 - 2/30

1 / (B's Rate) = 3/30

1 / (B's Rate) = 1/10    (taking reciprocal of both sides)

B's rate = 10 days to complete