Aaron and maria collected shells one morning at the beach. maria had 3 times as many as aaron, but they would have had the same number of shells if aaron had found 8 more and maria had found 6 less. how many shells did aaron collect?

Let the amount of shells collected by Aaron be and the amount of shells collected by Maria be respectively. Then the following system of equations should be solved:


First of all, express out of first equation:


Then, replace in second equation with found expression and solve it:




Finally, replace in first equation with found value and solve it too:



So, Aaron has found 7 shells while Maria has found 21.