Four cousins have an average age of 19 years. When a fifth cousin joins them, the average age becomes 21 years. How old is the fifth cousin (in years)?

Question

Accepted Answer

29. Sum of four ages = 4 × 19 = 76. Sum of five ages = 5 × 21 = 105. The fifth cousin is 105 − 76 = 29 years old.

Four cousins have an average age of 19 years. When a fifth cousin joins them, the average age becomes 21 years. How old is the fifth cousin (in years)?

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