# Downhill Slide to a World Record

Here's your nightly math! Just 5 quick minutes of number fun for kids and parents at home. Read a cool fun fact, followed by math riddles at different levels so everyone can jump in. Your kids will love you for it.

# Downhill Slide to a World Record

July 2, 2014

On a hot day, a fast way to cool off is to slide on a water slide. And that’s an easy thing to make: put a slippery sheet on a slope, point a running hose at it, and fling yourself onto it to zoom down the hill. Of course, as with everything, even the slip ‘n slide is part of a world record. A few days ago students in Mahwah, NJ broke the world record for the biggest total distance traveled on a slip ‘n slide. They built a slide nearly 75 feet long, then 250 kids slid down the hill over and over, until their sliding added up to more than 20 miles. It took about 1,400 total trips to get there! The kids worked as a team as part of town police department’s Leadership Academy. They may have been tired and worn out by the end, and maybe even a little bumped and bruised, but we know for sure that they definitely weren’t hot.

Wee ones: If you build 2 slip ‘n slides on your lawn, one 5 feet long and one 7 feet long, which one is longer?

Little kids: If it took your friend 13 seconds to slide down the slide and you then did it 1 second faster, how fast did you slide down?  Bonus: If 250 people were already sliding down the slide and you joined them, now how many people are in the group?

Big kids: If the hose had to gush 2 gallons of water for every trip, how many gallons of water were sprayed during the 1,400 trips?  Megabonus: If you want to do at least 1 mile of sliding yourself, how many trips do you need to take on the 75-foot slide? (Reminder: A mile has 5,280 feet.)

Answers:
Wee ones: The 7-foot slide.

Little kids: 12 seconds.  Bonus: 251 people.

Big kids: 2,800 gallons.  Megabonus: 71 trips. One way to solve this is by figuring out the distance for 10 trips – 750 feet – and using that to add up bigger chunks: 1,500 is 20 trips, 3,000 feet takes 40 trips. So 4,500 feet takes 60 trips. From there you can add another 10 trips (750) to get 5,250 feet in 70 trips, but you’re still short 30 feet, so add 1 more trip for 71.

### Laura Overdeck

Laura Bilodeau Overdeck is founder and president of Bedtime Math Foundation. Her goal is to make math as playful for kids as it was for her when she was a child. Her mom had Laura baking before she could walk, and her dad had her using power tools at a very unsafe age, measuring lengths, widths and angles in the process. Armed with this early love of numbers, Laura went on to get a BA in astrophysics from Princeton University, and an MBA from the Wharton School of Business; she continues to star-gaze today. Laura’s other interests include her three lively children, chocolate, extreme vehicles, and Lego Mindstorms.