In what year was Edward born?

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In what year was Edward born?

by VJesus12 » Mon May 21, 2018 7:48 am

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In what year was Edward born?

(1) In 1988, Edward turned 17 years old.
(2) Edward's sister Lisa, who is 14 months older than Edward, was born in 1970

The OA is the option A .

Why is the second statement not sufficient? Doesn't it imply that Edward was born in 1971? I need a clarification here? Please.

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by GMATGuruNY » Mon May 21, 2018 10:18 am

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VJesus12 wrote:
In what year was Edward born?

(2) Edward's sister Lisa, who is 14 months older than Edward, was born in 1970
Why is the second statement not sufficient?
Test EXTREMES.

Case 1: Lisa's birth month = January 1970
Since Edward was born 14 months earlier, Edward's birth month = November 1968.

Case 2: Lisa's birth month = December 1970
Since Edward was born 14 months earlier, Edward's birth month = October 1969.

Since Edward's birth year can be 1968 or 1969, INSUFFICIENT.
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by Vincen » Tue May 22, 2018 12:09 am

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VJesus12 wrote:In what year was Edward born?

(1) In 1988, Edward turned 17 years old.
(2) Edward's sister Lisa, who is 14 months older than Edward, was born in 1970

The OA is the option A .

Why is the second statement not sufficient? Doesn't it imply that Edward was born in 1971? I need a clarification here? Please.
(1) In 1988, Edward turned 17 years old.
If he turned 17 years old in 1988, then he was born in 1988-17 = 1971. SUFFICIENT.
(2) Edward's sister Lisa, who is 14 months older than Edward, was born in 1970
Since Lisa is older than Edward, this implies that he was born after 1970.

1- If Lisa was born between January and October 1970, then Edward was born between March and December 1971.
2- If Lisa was born in November or December 1970, then Edward was born in January or February 1972.

Since we've got two different years, this statement is NOT SUFFICIENT.

This is why the correct answer is the option A.

I hope it may help you.