Question

George is twice as old as Edward, and Edward's age exceeds Robert's age by 4 years. If the sum of the three ages is at least 56 years, what is Robert's minimum age?

Answer 1

Answer:Robert's minimum age is 11 years.

Explanation:

Let x represent George's age.

Let y represent Edward's age.

Let z represent Robert's age.

George is twice as old as Edward. It means that

x = 2y

Edward's age exceeds Robert's age by 4 years. It means that

z = y - 4

If the sum of the three ages is at least 56 years, it means that

x + y + z ≥ 56 - - - - - - - - - - 1

Substituting x = 2y and z = y - 4 into equation 1, it becomes

2y + y + y - 4 ≥ 56

4y - 4 ≥ 56

4y ≥ 56 + 4

y ≥ 60/4

y ≥ 15

z = y - 4 = 15 - 4

z ≥ 11