Question

PLEASE HELP

Ricardo is 4 years less than twice as old as his sister. The sum of their ages is 20. How old is Ricardo?

Answer 1

Given:

Ricardo is 4 years less than twice as old as his sister.

The sum of their ages is 20.

To find:

Ricardo's age.

Step-by-step explanation:

Let R be Ricardo's age.

Let S be his sister's age.

According to the question,

`\begin{gathered} R=2S-4............(1) \\ R+S=20...........(2) \end{gathered}`

Substituting equation (1) in (2) we get,

`\begin{gathered} 2S-4+S=20 \\ 3S-4=20 \\ 3S=24 \\ S=8 \end{gathered}`

Substituting S = 8 in equation (2) we get,

`\begin{gathered} R+8=20 \\ R=12 \end{gathered}`

Therefore, Ricardo's age is 12.

Final answer:

Ricardo's age is 12.