If a and b are integers and 9 < a < 21 and 19 < b &

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If a and b are integers and 9 < a < 21 and 19 < b < 31, what is the range of the possible values for a/b?

A) 12/19
B) 120/589
C) 12/31
D) 2/3
E) 480/589

The OA is the option D.

I don't understand how can I solve this PS question? What is the range? <i class="em em-confused"></i>
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by GMATGuruNY » Thu Mar 22, 2018 4:57 am
M7MBA wrote:If a and b are integers and 9 < a < 21 and 19 < b < 31, what is the range of the possible values for a/b?

A) 12/19
B) 120/589
C) 12/31
D) 2/3
E) 480/589
Since a must be an integer:
10 ≤ a ≤ 20.
Since b must be an integer:
20 ≤ b ≤ 30.

Greatest option for a/b:
(greatest possible a)/(smallest possible b) = 20/20 = 1.

Smallest option for a/b:
(smallest possible a)/(greatest possible b) = 10/30 = 1/3.

Range:
(greatest a/b) - (smallest a/b) = 1 - 1/3 = 2/3.

The correct answer is D.
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