Problem of the Week 05-01-2017

Lower Elementary:

Question:  Each of 10 cats has 10 kittens. Each of the kittens has 10 whiskers. How many kitten whiskers are there?

Answer:  1,000 whiskers

Solution:   If each of the 10 cats has 10 kittens, then there are 10 × 10 = 100 kittens. If each kitten has 10 whiskers, then there are 100 × 10 = 1,000 whiskers.

Upper Elementary:

Question:  Jessica has three cats. One is black, one is gray, and one is white. The white cat is not the oldest. The gray cat is older than the black cat. The black cat is younger than the white cat. Put Jessica’s cats in order from youngest to oldest.

Answer:  Black, white, gray

Solution:   Since the white cat is not the oldest, it can only be the youngest or middle cat. That means that for the gray cat to be older than the black cat, the gray cat has to be the oldest because the black cat and the white cat must be the two younger cats. Since the black cat is younger than the white cat, we can conclude that the order is black, white, then gray.

Middle School:

Question:  The cost per day of Kitty Kare cat sitters is $20 plus $8 per cat. Furbaby Sitters charge $25 and $4 per cat. Scott is going out of town for two days and needs a sitter for his three cats. How much money does Scott save by choosing Furbaby Sitters instead of Kitty Kare?

Answer:  $7

Solution:   Since Scott has three cats, Kitty Care costs $20 + $8 × 3 = $44 per day. Furbaby Sitters costs $25 + $4 × 3 = $37 per day. That means that Kitty Care would cost Scott $44 – $37 = $7 more per day. So, Scott saves $7 × 2 = $14.

Algebra and Up:

Question:  A cat starts chasing a mouse from 10 meters away. The cat runs at a rate of 14 meters per second, and the mouse scampers at a rate of 4 meters per second. How many seconds will it take the cat to catch the mouse?

Answer:  1 second

Solution:   Since the mouse starts 10 meters ahead, we need to set up an equation in which the distance the cat runs is 10 meters more than the distance the mouse runs: 14t = 10 + 4t. That’s equivalent to 10t = 10, so t = 1 second.