Herb has 13 toy cars. He keeps the cars in 2 cases. One has 3 more cars than the other case has. How many cars are in each case?
Let the numbers of cars in the first case is x and the number of cars in the second car be y.
The total number of cars is 13.
==> Then we can write :
x+ y= 13
But we know that one has 3 more than the other.
==> y= x+3
Now we will plug in y= x+3 into the first equation.
==> x +(x+3) = 13
==> 2x = 10
==> y= 8
Then, one case has 5 cars and the other has 8.