Log in

View Full Version : 7th grade gifted math conundrum


RobotBunny
Aug 30, 2009, 12:46 PM
I need help with this problem, I know there's something I'm not getting..
:confused:

The Bear family decided to open a cookie store that featured bear-sized cookies. Mama and Baby Bear decorated the cookies, and Papa Bear sold the cookies. Mama Bear could completely decorate a cookie every 7 minutes. Baby Bear could completely decorate a cookie every 12 minutes. Unfortunately, Papa Bear was eating one of the cookies every 9 minutes. If they open the store and have no cookies decorated, how long will it take them to produce 500 decorated cookies that can be sold?


Please explain too, so I know how to solve it, thanks!

HelpinHere
Aug 30, 2009, 01:18 PM
First, find the first factor if seven, twelve, and nine. Z

Seven x A = Z
Twelve x B = Z
Nine x C = Z

Then, add up A + B, it will become the total number of cookies made in Z minutes. Then, subtract C and you will have how many cookies can be sold in Z minutes. Y

(A+B)-C=Y

Then, you find the average time to make one sellable cookie, and multiply by 500 to get your answer.

Try doing that, and tell me what you get. If you need more help, I'll be glad to help.

RobotBunny
Aug 30, 2009, 02:09 PM
First, find the first factor if seven, twelve, and nine. Z

Seven x A = Z
Twelve x B = Z
Nine x C = Z

Then, add up A + B, it will become the total number of cookies made in Z minutes. Then, subtract C and you will have how many cookies can be sold in Z minutes. Y

(A+B)-C=Y

Then, you find the average time to make one sellable cookie, and multiply by 500 to get your answer.

Try doing that, and tell me what you get. If you need more help, I'll be glad to help.

Okay, sorry if I'm being a little stupid here, but what do you mean by first factor? If it's GCF then it's 1, right? A little more help, please? :o

galactus
Aug 30, 2009, 02:24 PM
I believe the LCM is what is meant. The smallest number that 7,12, and 9 divide into.

HelpinHere
Aug 30, 2009, 03:05 PM
Yep, I should have said "the first number they all factor into" which, as galactus stated, is also known as the least common multiple.

PS: Nice new pic galactus!

RobotBunny
Aug 31, 2009, 06:25 PM
Yep, I should have said "the first number they all factor into" which, as galactus stated, is also known as the least common multiple.

PS: Nice new pic galactus!

Thank you so much for your help! I did get the answer right, again, thanks!