Step-by-step explanation:
it takes Bailey b days to do the whole work alone.
so, he would be able to do 1/b of the whole work in one day.
it takes Andrew a = b/2 days to do the whole work alone.
so, he would be able to do 1/(b/2) = 2/b of the whole work in one day.
working together they each worked 5 days to complete the whole work (= 1).
5×1/b + 5×2/b = 1
5/b + 10/b = 1
5 + 10 = b
15 = b
it would take Bailey alone to finish the work in
15 days.
it would take Andrew alone to finish the work in
15/2 = 7 1/2 days = 7.5 days.
