You need to measure exactly 15 minutes.
How do you do it?
Solution[s] before the next post.
Start at same time. At 7' flip both. When 11 minute timer finished = 15'I think?
DRFlip them both over. When the 7 mins one runs out there'll be 4 mins left on the 11 mins one so now you'll know where the 4 mins mark is. Mark it. 11 + 4 = the desired 15 mins.Run the 11 mins one once then flip back and let the 4 mins out. Bob's your uncle and Fanny's your aunt.
https://www.popularmechanics.com/science/math/a27497/solution-to-riddle-of-the-week-33/
Or you could just use the 7-minute timer twice and say it's better to be early than late. ;)
I would ignore the timers and use my watch, but I always was a bit of a rebel.
I’d count out loud on my fingers.
11 - 7 = 4
Even I got that one.
Why are 11 and 7 minute timers called hourglasses?Other than as a means of impressing gullible girlfriends.
Comments need a moniker of your choosing before or after ... no moniker, not posted, sorry.
Start at same time. At 7' flip both. When 11 minute timer finished = 15'
ReplyDeleteI think?
DR
ReplyDeleteFlip them both over. When the 7 mins one runs out there'll be 4 mins left on the 11 mins one so now you'll know where the 4 mins mark is. Mark it. 11 + 4 = the desired 15 mins.
Run the 11 mins one once then flip back and let the 4 mins out.
Bob's your uncle and Fanny's your aunt.
https://www.popularmechanics.com/science/math/a27497/solution-to-riddle-of-the-week-33/
ReplyDeleteOr you could just use the 7-minute timer twice and say it's better to be early than late. ;)
ReplyDeleteI would ignore the timers and use my watch, but I always was a bit of a rebel.
ReplyDeleteI’d count out loud on my fingers.
ReplyDelete11 - 7 = 4
ReplyDeleteEven I got that one.
ReplyDeleteWhy are 11 and 7 minute timers called hourglasses?
ReplyDeleteOther than as a means of impressing gullible girlfriends.