Multiple choice

Three years ago, the average age of a family of 8 members was 30 years. If one child is also included in the family, the present age of the family remained unchanged. What is present age of the child? तीन वर्ष पहले एक परिवार के 8 सदस्यों की औसत आयु 30 वर्ष थी। यदि परिवार में एक बच्चे को सम्मिलित कर लिया जाए तो परिवार का वर्तमान औसत समान रहता है। बच्चे की वर्तमान आयु क्या है?

  1. 6 year/वर्ष

  2. 1 year/वर्ष

  3. 3 year/वर्ष

  4. 4 year/वर्ष
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Three years ago, average age of 8 members = 30 years, so total age = 8×30 = 240 years. Present total age of those 8 members = 240 + (8×3) = 264 years. When child (age x) is added, total members = 9 and total age = 264 + x. New average = (264+x)/9 = 30 (unchanged). Therefore 264+x = 270, so x = 6 years.

Keep practicing — related questions