Given that a and b are positive, is the ratio a:b...

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Given that a and b are positive, is the ratio a:b greater than 5?

1) a is 3 more than 5 times b.
2) The ratio of 4a to 5b is greater than 4.

The OA is D.

I'm really confused with this DS question. Please, can any expert assist me with it? Thanks in advanced.

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by DavidG@VeritasPrep » Wed Nov 08, 2017 10:51 am
LUANDATO wrote:Given that a and b are positive, is the ratio a:b greater than 5?

1) a is 3 more than 5 times b.
2) The ratio of 4a to 5b is greater than 4.

The OA is D.

I'm really confused with this DS question. Please, can any expert assist me with it? Thanks in advanced.
Rephrase the initial question:

Is a/b > 5?
Multiply both sides by 'b,' to get "Is a > 5b?" (Note that we can do this because b is positive, and thus we know that the inequality sign doesn't change.)

1) a > 5b + 3; Well if 'a' is greater than 3 more than 5b, then it must be more than 5b. Sufficient.
2) 4a/5b > 4
Divide both sides by 4 : a/5b > 1
Multiply both sides by 5b: a > 5b; thus, we've proved that a is greater than 5b. Sufficient.

The answer is D
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