Number Sense Blog

By Mathnasium | Added Apr 11, 2018

This week’s word problem challenge takes us back in time to the days of film and darkrooms. Once upon a time, before phone cameras and digital photography, people took pictures on this thing called film. The exciting thing about film photography is that you never know which photos will turn out well until you finish the roll and get the film developed.

Use your elementary and middle school math skills to help Tyler figure out how to get the average number of good photos he needs. (Hint: Multiplication and division skills will help you to determine the average.)

Question: Tyler shot 7 rolls of film. On each of the first 3 rolls, 16 photos turned out. Fourteen photos turned out on each of the next 4 rolls. If Tyler shoots 1 more roll of film, how many photos need to turn out for Tyler to have an average of 17 successful photos per roll?

Take your time working it out, and when you're ready, look below to check your solution with ours.

Solution: Tyler already has 3 × 16 + 4 × 14 = 104 good pictures. To average 17 good pictures per roll, he needs 17 × 8 = 136 pictures to turn out in total. So, Tyler needs 136 – 104 = 32 photos on the 8th roll to turn out.

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