Question

kethe and steve can complete a work in 12 days. Kethe alone can complete the same work in 20 days. if steve work only for half day daily, and then in how many days kethe and steve will together complete these work
1.20 days
2.18 days
3.15 days
4.12 days

Answer 1

together they can do the work in 12 days
in one day they do 1/12
in one day kethe does 1/20
so in one day Steve does
1/12-1/20=1/30
if Steve works half daily work done in a day 1/60
so together they do
1/20+1/60= 1/15
so they finish the work in
15 days
answer is
3. 15 days
=