Jane is x years old today. Her brother Kenny is 4 years older. After seven years their total combined age will be 24 years. Write a linear equation for their total combined age after seven years. Fine James age today.

Answer 1

x and x+4 forever

x + 7 + x+ 4 +7 = 2x + 18 = 24 after seven years
2x = 6
x = 3
x+4 = 7

so James is 3 now

Answer 2

Now:
Jane --- x
Kenny --- x+4

after 7 years:
Jane --- x+7
Kenny -- x+11

at that time:
x+7 + x+11 = 24
2x = 6
x=3

Jane is now 3, (where does James come in ? )

...... If you have to do it using 2 variables ....
jane now --- x
Kenny now -- y

y - x = 4 (#1)

x+7 + y+7 = 24
x+y = 10 (#2)
add #1 and #2
2y = 14
y = 7
x = 3
Same answer, but the first method looked easier.