wastedyouth wrote:

If a/b>4 . is a>8?

1) b>2.

2) a>7

Dear

wastedyouth,

I'm happy to help with this.

Here's a blog about DS questions with inequalities:

http://magoosh.com/gmat/2013/gmat-quant ... qualities/In this question, we are given that (a/b) > 4, and then we are asked: is a > 8?

Statement #1: b > 2Well, we know that

a = (a/b)*bWell, if the first factor,

(a/b) is greater than 4, and the second factor,

b, is greater than 2, then the product of something greater than 4 and something greater than 2 has to be greater than 8. Thus,

a must be greater than 8. This statement allows us to give a definitive answer to the prompt. This statement, alone and by itself, is

sufficient.

Statement #2: a > 7This doesn't involve b at all, so the fraction is irrelevant. We are left with --- if we know

a > 7, then is it true that

a > 8? Well, of course, it could be true: there are plenty of numbers greater than both 7 & 8 -----e.g. 9, 10, 11, 12, etc. BUT, it might not be true. For example, if

a = 8, then

a is greater than 7 but not greater than 8. Furthermore, nothing in the problem specifies that

a &

b are integers --- they are general numbers, so we have to keep our minds open to all categories of numbers. It turns out there is a continuous infinity of decimals greater than 7 and less than 8 --- the decimals in that single step of the number line outnumber all the atoms in the Universe! Any one of that infinity of values could be the value of

a, in which case

a would be greater than 7 but less than 8. Thus, we can find values of a that satisfy this statement and yet answer the prompt question either way. This statement does not determine a definitive answer. This statement, alone and by itself, is

insufficient.

Answer =

(A)Does all this make sense?

Mike

_________________

Mike McGarry

Magoosh Test Prep

Education is not the filling of a pail, but the lighting of a fire. — William Butler Yeats (1865 – 1939)