Question
Present average age of 4 friends: ‘A’, ‘B’,
‘C’ and ‘D’ is 20 years. If their ages are in the arithmetic progression in the same order and ‘D’ is 4 years older than ‘B’, then find the sum of present ages of ‘A’ and ‘C’.Solution
Common difference between ages = (4/2) = 2 years. So, let present ages of ‘A’, ‘B’, ‘C’ and ‘D’ be ‘x’, (x + 2) years, (x + 4) years and (x + 6) years, respectively According to question: x + x + 2 + x + 4 + x + 6 = 80 Or, 4x = 68 Or, x = 17 years (Age of A) Present age of ‘C’ = x + 4 = 17 + 4 = 21 years Required sum = 17 + 21 = 38 years
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