The two cans of broth used in the recipe total 2·14.5 oz = 29 oz. The number of people John wants to serve is 28/4 = 7 times the number served by one recipe. So, the amount of broth needed is ...
(29 oz)·7 = 203 oz
Each quart container of broth holds 32 oz, so John will need ...
(203 oz)/(32 oz/container) = 6 11/32 containers
John needs 6 11/32 containers of broth.
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If John must buy the broth, he must buy 7 containers. he will have 21/32 of a container left over after making his soup.
