Problems of the Week - December 13 to December 19

Rewards for Problems of the week:

5 stars for the correct answer at your level; 10 stars for the next level; 20 stars for 2+ levels up.

Lower Elementary:

Question: There are 51 kittens in a shelter. Seventeen of the kittens have black fur, 14 of the kittens have orange fur, and the rest of the kittens have white fur. How many kittens in the shelter have white fur?

Upper Elementary:

Question: It takes Andrew 25 minutes to build one bird feeder. If he needs to build seven bird feeders and has already finished three, how much longer will it take Andrew to finish the bird feeders?     

Middle School:

Question: After using her phone for 36 minutes, Scarlett notices that her battery indicator says that it is five-eighths full. If the battery was fully charged when Scarlett started using it, then how many minutes will the battery last on a full charge in total?

Algebra and Up:

Question: Mason and Natalie are painting fences. Mason can paint a fence in an hour. If Mason and Natalie work together, they can paint two fences in 1 hour and 12 minutes. How long will it take for Natalie to paint one fence by herself.

Challenge problem to take home. 5 stars for the correct answer. 

What is the minimum number of matchsticks that must be removed from this arrangement to leave exactly two squares?