A can paint a painting in 12 days. B can paint the same in 8 days. C can paint the same in 10 days. Find the (approximate) number of days in which the painting can be painted by A if he is accompanied by both B and C on alternate days and A starts painting on the first day alone.
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 5.4 days
Given that
A can paint a painting in 12 days. B can paint the same in 8 days. C can paint the same in 10 days.
A × 12 = B × 8 = C × 10
A : B : C = 10 : 15 : 12
Total work = 12 × 10 = 120 unit
if A is accompanied by both B and C on alternate days and A starts painting on the first day alone.
On the first day, A can do work alone 10 unit and On the second day A with B and C can do work (10 + 15 + 12) = 37 unit
then we can say that in 2 days, 47 unit work is completed
In 5 days, 104 unit work was completed and the remaining 16 unit work was completed in = 16/37 days
The total work of 120 unit was completed in = 5 + 16/37 days = 5.43 days