Question 1134753
Carlos is 3 years older than Juan. Jose is 4 years younger than Juan. The
sum of their 3 ages is 140. How old is Juan?
<pre>

Jose is the youngest, Juan the next youngest and Carlos is the oldest.
Carlos is 3 years older than Juan and Jose is 4 years younger than Juan. So

Let x = Juan's age 
Then Carlos's age is 3 years more than Juan's age, or x+3 
and Jose's age is 4 years less than Jose's age, or x-4

Since the sum of their ages is 140,

x + x+3 + x-4 = 140

You finish.

Edwin</pre>