A fraction becomes 4 when 1 is added to both the numerator and denominator, and it becomes 7 when 1 is subtracted from both the numerator and denominator. The numerator of the given fraction is : Pick one.
A) 2
B) 3
C) 7
D) 15
E) 17
Explanation:   Let the required fraction be a/b   Then a+1/b+1=4⇒a−4b=3   and a−1/b−1=7⇒a−7b=−6   Solving these equations we get,   a=15   b=3   Correct Option: 15
<result>D</result>
A fraction becomes 4 when 1 is added to both the numerator and denominator, and it becomes 7 when 1 is subtracted from both the numerator and denominator. The numerator of the given fraction is :