The age of Grace is 9 years old
Solution:
Given that sum of Ava’s and Grace’s age is 35
Ava is one year less than three times Grace’s age
To find: Age of Grace
Let "a" be the age of Ava
Let "g" be the age of Grace
According to given information,
sum of Ava’s and Grace’s age = 35
Ava age + Grace age = 35
a + g = 35 -------- eqn 1
Also given that Ava is one year less than three times Grace’s age
Age of Ava = three times Grace’s age - 1
a = 3g - 1 ---------- eqn 2
Let us solve eqn 1 and eqn 2 to find values of "a" and "g"
Substitute eqn 2 in eqn 1
3g - 1 + g = 35
4g - 1 = 35
4g = 36
g = 9
Thus the age of Grace is 9 years old