Thomas takes 7 days to paint a house completely whereas raj requires 9 days to paint the same house completely. how many days will take to paint the house if both them work together ?
Thomas takes 7 days to paint a house completely whereas raj requires 9 days to paint the same house completely. how many days will take to paint the house if both them work together ?
A. 3
B. 5
C. 4
D. 8
Answer : C. 4
Explanation:
No. of days taken by Thomas = 7 days.
So work done by thomas in a day = 1/7
No. of days taken by Raj = 9 days.
Work done by other in a day = 1/9
Work done by both in a day = 1/t
1/7 + 1/9 = 1/t
16/63 = 1/t.
16t = 63.
Days required by both (t) = 63/16.
Total no. of days taken to paint the house is (approx.) = 4 days .