Query Detail : RBI Grade B Phase I
A alone can do a work in 6 days and B alone in 9 days. If C takes twice as long as A and Btogether, how long will A and C together take to complete the same work?
Your Answer : 5 days
Correct Answer : 4 days
Garima, October 18th 2019,
RBI Grade B Phase I
LCM= 18 units
Eff of A = 3 units, Eff of B = 2 units
So C takes twice as long as A and B together So C is half efficienct of A & B together,
Eff. of C =(3+2)/2= 2.5 units
So A & C can do a job in = 18/(3+2.5) = 18/5.5 = 36/11
Can you please tell where you find this question, we will change it.
Thanks for pointing out!