Correct option is B
Total pages read by A and B in one hour = 88/11=8
Let efficiency of A = 5x pages/hour
So, efficiency of B = 60% of 5x =3x pages/hour
5x + 3x = 8
x = 1
Efficiency of C = 150/10 – (5+3) = 7 pages/hours
So, required time = 120/((7+3)) = 12 hours