How old is Robert,if Marin is 9 years older than him and their ages make 21?
R + R + 9 = 21
2R = 12
R = 6
Thank you, but could you explain this solution for me , please?
R = Robert
R + 9 = Marin
Their two ages = 21.
The equation and its solution should be obvious.
Thank you very much.
You are very welcome.
To determine Robert's age, you can set up a system of equations using the given information. Let's denote Robert's age as 'R' and Marin's age as 'M'.
According to the information provided, we know that Marin is 9 years older than Robert: M = R + 9.
We are also told that their ages combined make 21 years: R + M = 21.
To find Robert's age, we can substitute the first equation into the second equation:
R + (R + 9) = 21
Simplifying this equation:
2R + 9 = 21
2R = 21 - 9
2R = 12
R = 12 / 2
R = 6
Therefore, Robert is 6 years old.