A can do a certain work in 40 days. B is 60% more efficient than A. Both work together for 10 days. C alone completes the remaining work in 10
2
1
​
days. Working together, B and C can complete 44% of the original work in:

Let the efficiency of A be 5 units/day.
Since B is 60% more efficient than A, efficiency of B =5×1.6=8 units/day.

Total Work =Efficiency of A×Days=5×40=200 units.

A and B work together for 10 days:

Work done by A and B=(5+8)×10=13×10=130 units
Remaining Work=200−130=70 units
C completes the remaining work in 10
2
1
​
=
2
21
​
days:

Efficiency of C=
2
21
​

70
​
=
21
140
​
=
3
20
​
 units/day
Combined efficiency of B and C:

Efficiency of B + C=8+
3
20
​
=
3
44
​
 units/day
We need to find the time taken to complete 44% of the original work:

Targeted Work=44% of 200=
100
44
​
×200=88 units
Time taken by B and C:

Time=
3
44
​

88
​
=
44
88×3
​
=2×3=6 days