So, Barry bought 4 packs of snowflakes and each pack contains 20 stickers. Therefore, we do 4 x 20, which is 80, so he has 80 snowflake stickers. Then, he also bought 2 packs of dinosaurs, and each pack of dinosaur stickers has 17 stickers. So, we need to do 2 x 17 which is 34, so he has 34 dinosaurs stickers. In total, Barry has 114 stickers, now we need to remember how many stickers in total he has for later. Let's move on to Amy. Amy bought 3 packs of snowflakes, and because each pack contains 20 stickers, we do 3 x 20 which equals 60. Therefore, Amy has 60 snowflake stickers. Then, Amy bought 3 packs of rose stickers, so because each pack of rose stickers has 25 stickers, we do 3 x 25 which is 75. So, Amy has 135 stickers in total. Now let's add up both of their totals to see if we have 300 stickers. So, if we add 135 and 114 we get 249, we do not have enough stickers. Let's find out how many stickers they still need to buy. Now, we do 300 (Because 300 is the amount we need to have) minus 249 (Because that is the amount we have) which equals 51. So, they need to buy 51 more stickers because that is what they are missing from the total they need. Therefore, the answer is A. 51.
