Answer:
Leo is 11 years old
Explanation:
* Lets explain how to solve the problem
- Alea is 5 times 3 less than leo's age
- Alea is 40 years old
- Assume that leo's age is x
* Lets change the words to equation
∵ Leo is x years old
∵ Alea is 5 times 3 less than Leo's age
- That means when we subtract 3 from Leo's age and multiply the
difference by 5 the result is Alea's age
∴ Alea's age = 5(x - 3)
- Multiply the two terms of the bracket by 5
∴ Alea's age = 5x - 15
∵ Alea is 40 years old
- Equate the expression of Alea's age by her age
∴ 5x - 15 = 40 ⇒ the equation to find Leo's age
- Add 15 to both sides
∴ 5x = 55
- Divide both sides by 5
∴ x = 11 ⇒ the solution of the equation
∵ x represents the Leo's age
∵ x = 11
∴ Leo is 11 years old