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?

Ages at equal gaps form an arithmetic sequence, like seats numbered every third row. The middle child's age is the average. With 5 children summing to 50, the average (and the middle child) is 10, so step back two gaps of 3 to reach the youngest.

Question: 5 children, 3 years apart, total age 50. Youngest?

Method 1:

1. Ages: x, x + 3, x + 6, x + 9, x + 12.
2. Sum = 5x + 30 = 50, so x = 4.

Method 2 (middle term):

1. Average = 50 / 5 = 10, the middle child.
2. Youngest = 10 - 2 x 3 = 4.

Ages: 4, 7, 10, 13, 16. Sum = 50.

const ages = [0, 1, 2, 3, 4].map(i => 4 + 3 * i);
console.log(ages); // Output: [4,7,10,13,16]
console.log(ages.reduce((a, b) => a + b)); // Output: 50

• Using x + 3, x + 6 ... up to x + 15, which describes 6 children.
• Answering with the eldest child's age.