# Problem of the Week July 15th

Jul 14, 2018 | Mesa North

Lower Elementary:

Question: Alice the librarian has a cart of 3 dozen books to put back on the shelves. She puts 3 of them away before she’s startled by a ghost and runs away. How many books does Alice leave on her cart?

Upper Elementary:

Question: Peter and Ray walk 4½ miles to get to the library to investigate some paranormal activity. If they can walk 3 miles in 1 hour, then how many minutes does it take them to get to the library?

Middle School:

Question: A paranormal activity hotline receives 1,000 calls per hour, 24 hours per day, for 6 weeks straight. The paranormal investigators only respond to 2% of those calls. How many calls do the investigators respond to in 6 weeks?

Algebra and Up:

Question: A 6-inch tall marshmallow man has a volume of 15 cubic inches. If the marshmallow man magically increases in size so that he grows proportionally to a height of 100 feet, then what is his new volume?

WARNING! ANSWERS AND SOLUTIONS COMING UP!

Lower Elementary:

Question: Alice the librarian has a cart of 3 dozen books to put back on the shelves. She puts 3 of them away before she’s startled by a ghost and runs away. How many books does Alice leave on her cart?

Solution:  Since a dozen is 12, Alice starts with 12 + 12 + 12 = 36 books. After she shelves 3 of them, there are 36 – 3 = 33 books left on the cart.

Upper Elementary:

Question: Peter and Ray walk 4½ miles to get to the library to investigate some paranormal activity. If they can walk 3 miles in 1 hour, then how many minutes does it take them to get to the library?

Solution:  Since 3 miles goes into 4½ miles 1 times, it takes Peter and Ray 1½ hours to walk to the library. An hour is 60 minutes, so 1½ hours is 60 × 1½ = 90 minutes.

Middle School:

Question: A paranormal activity hotline receives 1,000 calls per hour, 24 hours per day, for 6 weeks straight. The paranormal investigators only respond to 2% of those calls. How many calls do the investigators respond to in 6 weeks?

Solution:  If the investigators respond to 2% of the calls, they respond to 0.02 × 1,000 = 20 calls per hour. So, they respond to 20 × 24 = 480 calls per day. There are 7 days in a week, so 6 weeks is 42 days. That means that the investigators respond to 480 × 42 = 20,160 calls in 6 weeks.

Algebra and Up:

Question: A 6-inch tall marshmallow man has a volume of 15 cubic inches. If the marshmallow man magically increases in size so that he grows proportionally to a height of 100 feet, then what is his new volume?