The sum of the ages of 5 children born at intervals of 3 years each is 50 years. What is the age of the youngest child?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 4 years
The children were born 3 years apart, so each is 3 years older than the next. Let the youngest be \(x\) years old; the ages are then \(x\), \(x+3\), \(x+6\), \(x+9\) and \(x+12\).
\(5x+30=50\)
\(5x=20\)
\(x=4\)
Shortcut: The ages are equally spaced, so the average age is the middle child’s age.
Middle (third) child: \(50\div5=10\) years
Youngest, two gaps of 3 years younger: \(10-6=4\) years