Divide the total cost by the number of tulip bulbs bought to find the price of one bulb, then you can compare each store:
Store A:
5 bulbs for $11.00
11.00 / 5 = $2.20 per bulb
Store B:
6 bulbs for $13
13 / 6 = $2.17 per bulb
The two stores have different rates. Store B is cheaper.
