It’s a word problem that says, “Grace is 9 years old and Ruth is 6 years older than Grace. Express Ruth’s age as a fraction of their total age in lowest terms.”
OK, the forst thing we have is: Grace is 9 years old.
So, let us write G = 9, where G is the age of Grace.
The next thing we have is: Ruth is 6 years older than Grace.
So, let us write R = G + 6, where R is the age of Ruth.
Our two equations now are,
G = 9
R = G + 6
So, very obviously, R = 15
And total age is T = R + G = 15 + 6 = 21.
What we want is: Express Ruth’s age as a fraction of their total age in lowest terms.
i.e. R/T = 15/21 = 5/7