The present age of Cesar is 38 years old
Solution:
Let the present age of Cesar be "a"
Let the present age of Hillary be "b"
Cesar is 5 years older than Hillary
Present age of Cesar = 5 + present age of Hillary
a = 5 + b ------ eqn 1
In 9 years the sum of their ages will be 89
Age of cesar after 9 years = a + 9
Age of hillary after 9 years = b + 9
Sum of their ages is 89
Therefore,
a + 9 + b + 9 = 89
a + b = 89 - 18
a + b = 71 -------- eqn 2
Substitute eqn 1 in eqn 2
5 + b + b = 71
5 + 2b = 71
2b = 66
b = 33
Substitute b = 33 in eqn 1
a = 5 + 33 = 38
Thus present age of Cesar is 38 years old