simplyfy

[uptowngirl92]

If x = 4 and y = 16, then sq. root of (x+y/xy) is closest to which of the following ?

(A) 1/3
(B) 1/2
(C) 3/4
(D)7/8
(E) 1

[spoiler]OA:B[/spoiler]

Ok so i got stuck in the last step.Simplified and got sq root of 5/4.Now what if I have no clue of wat the value of sq root of 5 is?My ans was C because i know sq root of 4 is 2.So sq root of 5 should be a value 2+.I already have the denominator as 4.So C.CLearly the logic is wrong.

[ssmiles08]

You dont need to know what sqroot of 5 is.

Think of it this way: sq(4)<sqrt(5)<sq(9)

which means 2<sqrt(5)<3

sqrt(5) is closer to 2 in this case than to 3, so it is fair to approximate it around 2 (sqt(5) = 2.2)

so (16+4)/(4*16) = 5/16--->sqrt that = sqrt(5)/4 ~ 2/4 = 1/2 (B)