Question

Luis and Roberto are donating some of their baseball cards to the library. Luis started with 50

cards and gave away X number of them. Roberto started with 80 cards and gave away 3 times as
many as Luis had given away.
If they both now have the same number of baseball cards, how many baseball cards did Roberto
give away?

Answer 1

X=15

Explanation:

50−x=80−3x

Step 1: Simplify both sides of the equation.

50−x=80−3x

50+−x=80+−3x

−x+50=−3x+80

Step 2: Add 3x to both sides.

−x+50+3x=−3x+80+3x

2x+50=80

Step 3: Subtract 50 from both sides.

2x+50−50=80−50

2x=30

Step 4: Divide both sides by 2.

2x \2 = 30 \2

Answer:

x=15