Select the bubbles that do not represent a ratio.
A and 13 together can do a piece of work in 12 days: B and C can do it in 20 days whilci C and A can do it in 15 days. A. B and C all working together can do it In
(a) 6 days
(b) 9 days
(c) 10 days
(d) 1012 days
A can do a piece of work in 15 days. 13 is 50% more efficient than A. B can finish it in
(a) 10 days
(b) 712 days
(c) 12 days
(d) 1012days