So, we can easily set this up in an equation. X represents the number of soccer balls in store one, and Y represents the number of soccer balls in store two. Since there's a total of 70 soccer balls...
And since we know how much money they sold for and made total...
We'll grab that first equation and change it around a bit. We'll make it an equation where we're solving for y. Remember that when we switch a value from one side to the other, that value becomes negative. Since x is going to the other side, the x becomes negative.
We can plug this equation into our second one.
We distribute the 65 to the values inside the parentheses.
We only want x on the left side, so we're going to subtract 4550 from both sides.
Then we can subtract 15x by 65x, resulting in another negative number.
Then, we just divide both sides by -50. A negative and a negative makes for a positive.
Now we know one store sold 43 soccer balls for $15 each. We can plug our new x into the first equation.
Then we subtract both sides by 43.
Now we know the other store sold 27 soccer balls for a whopping $65 each. Just to double check, we'll plug our numbers into the other equation, too.
Yep! So, we end up with one store selling 43 and the other selling 27.