Problem of the Week 04-18-2017

Lower Elementary:

Question: Stacy has tickets to a concert that starts at 8:30 pm. If it’s currently 7:42 pm, then how much time does Stacy have to get to the concert before it starts?

Answer:  48 minutes

Solution:  We can solve this problem by building up to 8:30. There are 18 minutes until 8:00 because 42 + 18 = 60 minutes, or an hour. There are 30 minutes from 8:00 until 8:30. So, Stacy has 18 + 30 = 48 minutes until the concert starts.

Upper Elementary:

Question: Maggie wants to buy a puzzle that costs $25. She has a 50% off coupon and $10. How much more money does Maggie need to get the puzzle?

Answer:  $2.50

Solution:  Half of $25 is $12.50. Maggie already has $10, so she needs $12.50 – $10 = $2.50 more.

Middle School:

Question: A red token is worth twice as much as an orange token. An orange token is worth 5 less a yellow token. A yellow token is worth 15 less than a green token. A green token is worth half as much as a blue token, and a blue token is worth B. How much is a yellow token worth in terms of B?

Answer:  0.5B – 15

Solution:  If a blue token is worth B, then a green token is worth half of B, or 0.5B. A yellow token is worth 15 less, so that’s 0.5B – 15.

Algebra and Up:

Question: The formula for the temperature in Fahrenheit (F) in terms of the temperature in Celsius (C) is:

F = ^9C/₅ + 32

What is the formula for the temperature in Celsius in terms of the temperature in Fahrenheit?

Answer:   C = ⁵/₉(F – 32)

Solution:  First, we subtract 32 from both sides and get F – 32 = 9C ÷ 5. Next, we multiply each side by 5 and get 5(F – 32) = 9C. After that, we divide each side by 9 and get ⁵/₉(F – 32) = C. Finally, we flip it around and get C = ⁵/₉(F – 32).