Luis purchased 6 postcards for $3.30. Mrs. Robbini spent $35.20 on postcards at the same price per card. How many postcards did Mrs. Robbini buy?
64 postcards
40 postcards
96 postcards
55 postcards

please answer fast! And no links or I’ll report

First we need to find unit rate, which means how much each postcard cost. Therefore we can do 3.30 divided 6 which give us 0.55 per post card. We can check to see if this is correct by plugging 0.55(6) which gives us 3.30 dollars. Now to find Ms.Robbini you can do 35.20 divided by 0.55 which gives us 64. So now we know that Ms.Robbini spent 35.20 dollars on 64 postcards.