245 IS BETWEEN WHICH OF THE FOLLOWING PAIRS OF INTEGERS A4 A

Solution

sqrt(245)

factorise 245 = 5*49 = 5*7*7

So, sqrt245 = sqrt(5*7*7) = 7*sqrt(5)

2<sqrt5<3

So, sqrt245 lies between : 7*2 <x <7*3 = 14<x < 21

The option which satisfies the above range is option B 15 and 16