Q9 of 83 Page 90

Product of the ages of Virat 7 years ago and 7 years later is 480. Find his present age.

Let the present age of Virat be x yrs.

⇒ His age 7 yrs ago was = (x – 7) yrs. and 7 years later will be = (x + 7) yrs.


⇒ (x – 7)(x + 7) = 480


⇒ x2 – 49 = 480


⇒ x2 – 49 – 480 = 0


⇒ x2 – 529 = 0


⇒ x2 – 232 = 0


⇒ (x + 23)(x – 23) = 0


⇒ x + 23 = 0 or x – 23 = 0


⇒ x = 23 or x = – 23


But age cannot be negative


⇒ x = 23 years.


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