(b) 315
The class having the maximum frequency is the modal class.
So, the modal class is 150 – 155 and its lower limit is 150.
Also, N = 60 ⇒ N/2 = 30
The cumulative frequency just more than 30 is 37 and its class is 160 – 165, whose upper limit is 165.
∴ Required sum = (150 + 165) = 315