math word problem
posted by marko .
word problem need help:
suppose you own a card shop. you buy one line of cards at a rate of 4 cards for $5.
you plan to sell the cards at a rate of
3 cards for $5
how may carfds must you sell in order to make a profit of $100.00
i don't understand how to get answer can you help

5/4 = 1.25 >> amount paid for each card
5/3 = 1.67 >> amount received for each card
1.67  1.25 = 0.42 profit on each card.
100 / 0.42 = 238.1 = 239 cards to make a profit of at least $100.