sqrt(10)

[blaster]

Of the following, which is most nearly equal to sqrt(10)?

(A) 3.1
(B) 3.2
(C) 3.3
(D) 3.4
(E) 3.5

what is the best an fastest approach for this kind of questions?

[Anurag@Gurome]

Of the following, which is most nearly equal to sqrt(10)?

(A) 3.1
(B) 3.2
(C) 3.3
(D) 3.4
(E) 3.5

Probably the best approach is to calculate the square root of 1000 and then put a decimal in the result.

Guess a square number in the vicinity of 1000. Say we start with 900. Then,

• (30)^2 = 900
  (31)^2 = 961 .... More towards 1000
  (32)^2 = 1024 .... More than 1000

Now, 1024 is more nearer to 1000 than 961. Hence sqrt(1000) will be more near to 32. Thus sqrt(10) will be more near to 3.2.

The correct answer is B.