Answer:
7 Apples
Explanation:
For this question, we can write expressions for Maria's apples and Luigi's apples and form an equation as they end up with the same amount.
Mario starts with 12 apples but gives away x number. This means Mario's final amount of apples can be represented as: 12-x
Similarly Luigi starts with 26 and gives away 3 times the amount of Mario. So the number he gave away can be represented as: 3x (3 times the number Mario gave away). Therefore we can represent Luigi's final number as: 26-3x
Since they both end up with the same number of apples, we can put these expressions equal to each other in an equation to solve for x (the number of apples Mario gave away):
Mario Luigi
12-x = 26-3x
12-x=26-3x
Now we just need to move the unknowns to one side and the other terms to the other, combine and solve:
12-x-12=26-12-3x
-x=14-3x
-x+3x=14-3x+3x
2x=14
2x/2=14/2
x=7
Mario gave away 7 apples.
Hope this helped!