Derek bought 4 pounds of tomatoes at the grocery store. This included grape, roma, and plum tomatoes. If Derek bought 2 pounds of grape tomatoes and 14 ounces of roma tomatoes, how many ounces of plum tomatoes did he buy?

The answer is he used 18 ounces.

Convert this first to pounds to ounces. We know that there are 16 ounces in one pound, so therefore he 4 x 16 = 64. So he has a total of 64 ounces.

Two pounds of grape tomatoes would be equal to 32 ounces

The roma tomatoes are when computed is 14 ounces.

32 + 14 = 46 (Grape + Roma)

Total - (Grape + Roma) = Plum

64 - 46 = 18