Question

# If twice the  reciprocal of a positive number is subtracted from the same number, we get 1. Find the number.3124

Solution

## The correct option is C 2Let the number be x. Reciprocal of a number = 1x Twice the reciprocal = 2x According to the given condition, x−2x=1 x2−2=x x2−x−2=0 Quadratic formula is given by, x=−b±√b2−4ac2a Here, a=1,b=−1 and c=−2 ⇒x=1±√1−(4×1×−2)2         =1±√1+82         =1±√92          =1±32 ⇒x=2 ,−1 As the number is positive, ignore negative value. Hence, x = 2 ​∴ The required number is 2.

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