2023 · Q4
If A and B can finish a work in 10 days, B and C can finish the same work in 12 days, C and A can finish the same work in 15 days; then in how many days can A, B and C together finish half of the work?
Elementary MathematicsTime and Work
- A8 days
- B5 days
- C4 days
- D3 days
Explanation
1/x+1/y=1/10, 1/y+1/z=1/12, 1/z+1/x=1/15. Adding: 2(1/x+1/y+1/z)=(6+5+4)/60=1/4, so together they do 1/8 per day. Full work takes 8 days, half takes 4 days. Option (c).