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In a pet shop, there are $3$ hamsters for every $2$ guinea pigs, and there are $2$ giant cloud rats for every $3$ guinea pigs. If $N$ is the total number of hamsters, guinea pigs, and giant cloud rats, and $N>0$, then what is the smallest possible value of $N$?

 Jan 13, 2017

Best Answer 

 #2
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+5

From your problem, we can represent the number of hamsters, guinea pigs, and giant cloud rats with the letters H, G, and R respectively. Therefore, the following equations are true:

 

2H = 3G

3R = 2G

N = R + G + H

 

Now we can solve for R and H in the upper equations with respect to G and substitute them into the lower equation:

 

H = 3/2G

R = 2/3G

N = 2/3G + G + 3/2G

 

Simplifying gives: 

 

N = 19/6G

 

Since N must be a whole number, G has to be a multiple of 6 for this equation to make sense. Therefore, we will use 6 for G to find that N=19. 

 

Checking your work will indicate that there are 6 Guinea Pigs, 9 Hamsters, and 4 Giant Cloud Rats, and this is indeed the smallest combination of the three with all else being true. 

 Jan 13, 2017
 #1
avatar+118658 
0

 

I have set up the 2 ratios here.  You must keep the same ratios but make the number of guinea pigs the same.

The lowest common multiple of 2 and 3 is 6

 

 

H G     R G
3*3 2*3     2*2 3*2
9 6     4 6

 

So this is the ratio of the animals

 

H R G Total
9 4 6 18
     

N=18k  

(where k is an integer)

 

The number of animals in total is a multiple or 18.  The smallest number is 18    :)

 Jan 13, 2017
 #3
avatar+118658 
+5

Yep, guest is right, I cant add up properly LOL

9+4+6=19  !!

 

 

Thanks guest ;)

Melody  Jan 13, 2017
 #2
avatar
+5
Best Answer

From your problem, we can represent the number of hamsters, guinea pigs, and giant cloud rats with the letters H, G, and R respectively. Therefore, the following equations are true:

 

2H = 3G

3R = 2G

N = R + G + H

 

Now we can solve for R and H in the upper equations with respect to G and substitute them into the lower equation:

 

H = 3/2G

R = 2/3G

N = 2/3G + G + 3/2G

 

Simplifying gives: 

 

N = 19/6G

 

Since N must be a whole number, G has to be a multiple of 6 for this equation to make sense. Therefore, we will use 6 for G to find that N=19. 

 

Checking your work will indicate that there are 6 Guinea Pigs, 9 Hamsters, and 4 Giant Cloud Rats, and this is indeed the smallest combination of the three with all else being true. 

Guest Jan 13, 2017
 #4
avatar+129839 
0

R   = cloud rats                           2

(3/2)R  = guinea pigs                  3

(3/2) [(3/2)R]  = hamsters           9/2   

 

So...since we can't have 9/2  hamsters.....we need to multiply by 2

 

 

R   = cloud rats                        2  * 2   =  4

(3/2)R  = guinea pigs               3  * 2  =   6

(3/2)(3/2)R  = hamsters           9/2 *2  =  9

 

So...the smallest that N  can be =  4 + 6 + 9  =  19 

 

 

 

cool cool cool

 Jan 13, 2017

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