Answer: 5 months
Step-by-step explanation:
okay we set up and equation.
10 + 5m is how many cards will gets, where m is months
20 + 3m is how many cards thomas gets, where m is months.
lets see how many months it will take for them to be equal:
10 + 5m = 20+ 3m
5m = 10 +3m
2m = 10
m = 5
it will take 5 months for them to have the same amount of cards.