1 year from now Mike will be 40 years old. The current sum of the ages of Mike and John is 89. How o

1 year from now Mike will be 40 years old. The current sum of the ages of Mike and John is 89. How old is John right now?

If Mike will be 40 1 year from now, then he is:
40 - 1 = 39 years old today.

And if the current sum of Mike and John's age is 89, then we use j for John's age:
j + 39 = 89

Type this equation into our search engine, and we get:
j = 50