This Week From Bedtime Math: Extreme Grilling

If you&ve invited too many people to your BBQ, you might be feeling the heat. Try these math challenges to keep everyone from "flipping out."
By Laura Overdeck
Jul 29, 2014



Jul 29, 2014

What is Bedtime Math? A message from Laura: Bedtime Math is a pretty simple idea: We all know we should read to our kids at night, but what about math? My husband and I have done fun, mischief-loaded math problems with our kids at night for years, and when at age 2 our third child started hollering for his own math problem, we realized we were onto something:  In a world where so many people say, "Ewww, math!" we had created a household culture where kids don't just tolerate math, they actually seek it out. Now, every week, we'll be posting a new problem right here on Scholastic Parents!
Summer is made for outdoor barbecuing, when everyone gathers around a grill in the U.S. It's dads' chance to prove they can cook something, and to pretend they're just wowing the kids when the food catches on fire. But being the grillmaster or grill diva is high pressure. Not all foods cook for the same amount of time, nor do they take up the same amount of space on the rack. Never mind which people want it rare (lightly cooked) vs. well-done (cooked to a crisp). It's a giant flame-throwing juggling act, no matter how you cook up the numbers.

Here's your chance to cook up some math skills with these challenges for your kids:

Wee ones: Which grill holds more food: one that can fit 8 burgers or one that can fit 6 burgers?

Little kids: If the grillmaster needs to cook 3 hot dogs, 1 steak, and 5 ears of corn, how many food items need to fit on the grill?  Bonus: If the grill can hold 16 hot dogs, but 3 of them line up the wrong way and fall through the rack, how many hot dogs are left?

Big kids: If the grillmaster has to cook for 14 people and everyone wants 1 hot dog and 1 veggie burger, how many items does he/she have to grill? (Don't worry about the rolls.)  Bonus: Let's say burgers take 8 minutes to cook. If the grillmaster cooks 4 rounds of burgers, with each round starting only 3 minutes after the previous round started, what's the end-to-end burger-cooking time?

The sky's the limit: If the grill can hold 10 hot dogs or 5 burgers, and hot dogs take 5 minutes and burgers take 8 minutes…what's the fastest you can cook 12 hot dogs and 6 burgers? (Assume any chunk of space can hold either 2 dogs or 1 burger.)

Wee ones: The 8-burger grill.

Little kids: 9 items.  Bonus: 13 hot dogs left.

Big kids: 28 items.  Bonus: 17 minutes total. The 1st starts at 0 minutes, so the 4th round (i.e., 3 rounds later) starts cooking at 9 minutes. Then it takes an additional 8 minutes beyond that.

The sky's the limit: The fastest we got here is 16 minutes, by running 4 hot dogs (2 burger spaces) and 3 burgers (3 spaces) at a time. The 12 hot dogs cook in 3 rounds, requiring 15 minutes; in parallel the 6 burgers cook in 2 rounds, which take just 1 minute longer at 16 minutes. Note that cooking all the hot dogs before all the burgers doesn't go faster. You cook the first 10 dogs, then 2 final dogs with the first 4 burgers…but you can replace those 2 dogs with only the 5th burger, so the 6th burger has to wait until the first 4 burgers finish. That means a 3rd round of burger-cooking, making 5 minutes plus 2 sets of 8 minutes. If you find an even faster time, let us know!

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