Solve this!

[Reasonable Doubt]

 

[MagnusTheBrewer]

27 kg

 

[Crono]

27

EDIT: Beat to it

 

[Printer Bandit]

animals can't read a scale.

 

[Ruptga]

I was also beat to it, but it's a pretty straightforward algebra problem, and WolframAlpha would have no problem figuring it out if you couldn't be bothered to do the math.

 

[MagnusTheBrewer]

I was also beat to it, but it's a pretty straightforward algebra problem, and WolframAlpha would have no problem figuring it out if you couldn't be bothered to do the math.

You have to set it up first which is the difficult part. Solving problems is never hard when you understand the relationship.

 

[brianmanahan]

cat + bunny = 10
dog + bunny = 20
dog + cat = 24

dog + (10 - bunny) = 24
dog = bunny + 14

(bunny + 14) + bunny = 20
2*bunny = 6
bunny = 3

dog = 17
cat = 7

17 + 7 + 3 = 27

 

[brianmanahan]

i could have probably solved that a lot easier w/ linear algebra

too bad i forget most of it

 

[Fenixgoon]

its just a linear algebra problem. 3 equations, 3 unknowns.

 

[MagnusTheBrewer]

cat + bunny = 10
dog + bunny = 20
dog + cat = 24

dog + (10 - bunny) = 24
dog = bunny + 14

(bunny + 14) + bunny = 20
2*bunny = 6
bunny = 3

dog = 17
cat = 7

17 + 7 + 3 = 27

I took a different route.
cat + dog + 2 bunnies = 30
30 - (cat + dog) = 6 = 2 bunnies
bunny + cat + dog = 27

 

[Ruptga]

You have to set it up first which is the difficult part. Solving problems is never hard when you understand the relationship.

That's generally true, but not in the case of WolframAlpha.
http://www.wolframalpha.com/input/?i=a+b=10,+b+c=20,+a+c=24+find+a+b+c

All you have to do is enter the relationships in terms that it can understand, you don't have to know anything about how it's solved, for the most part.

 

[brainhulk]

Its a clock, notice how the hand never moves . The animals think it's a scale. They are each verbalizing what they think they see. But when the ? Comes up, the dog thinks to himself ? Kg

 

[IronWing]

27

I crowd sourced it.

 

[MagnusTheBrewer]

That's generally true, but not in the case of WolframAlpha.
http://www.wolframalpha.com/input/?i=a+b=10,+b+c=20,+a+c=24+find+a+b+c

All you have to do is enter the relationships in terms that it can understand, you don't have to know anything about how it's solved, for the most part.

Abstract thinking is the difficulty I'm talking about. It's simple to you because you've learned and practiced to think that way. To put it another way, have you ever observed the frustration older folks who have never used a smartphone have trying to do a simple (to you) task?

One of my biggest frustrations in studying programming is how much Universities expect students to have internalized and never speak about basic relationships. Math isn't taught that way. Identities and relationships are clearly explained and students aren't expected to have 'picked it up' elsewhere. I call it the secret handshake conspiracy.

 

[Ruptga]

Oh, yeah I see what you're saying. I looked at the picture and instantly knew that the animals could be treated as variables, etc.

I'm actually a freshman in a programming program right now. At the moment, this is my bible. MST's CS program doesn't assume that its students know much of anything, as it says there on the main page.

 

[TuxDave]

cat + bunny = 10
dog + bunny = 20
dog + cat = 24

Add all three lines up.
2cat+2dog+2bunny=10+20+24=54
cat+dog+bunny=27

None of this substitution jibba jabba.

 

[yhelothar]

Pretty easy to see that the cat weighs 4kg more than the bunny right off the bat.

Then you just need two numbers that differ by 4 that add up to 10, which is 7 and 3 for the cat and rabbit, respectively, which makes the dog weigh 17. 17+7+3=27.

 

[Rakehellion]

Where is everyone getting 2 bunnies? Seems like that overcomplicates the problem.

 

[El Guaraguao]

animals can't read a scale.

Why anyone would even still try to math this, is beyond me. GJ PB.

 

[brianmanahan]

Where is everyone getting 2 bunnies? Seems like that overcomplicates the problem.

bunnies multiply so fast, you cant avoid it

 

[DrPizza]

Add all three lines up.
2cat+2dog+2bunny=10+20+24=54
cat+dog+bunny=27

None of this substitution jibba jabba.

Yep, that was the first way I noticed when looking at the pics. Add the first 3 pics together, divide by 2. It's a great problem to use in common core algebra.

It also illustrates a new method, which I would refer to as think first before jumping into some rote method you learned. Using a similar problem, you can design a system with no unique solution for the individual weights, but which has a solution for the sum.

 

[TheVrolok]

Add all three lines up.
2cat+2dog+2bunny=10+20+24=54
cat+dog+bunny=27

None of this substitution jibba jabba.

Same thing I did. Fun problem.

 

[GagHalfrunt]

Where's the obligatory "do your own homework" reply? ATOT is a slipping.

 

[SKORPI0]

27

I crowd sourced it.

D:.................:awe:.................:biggrin:

Now solve this!!!!!

Solution - http://www.waytomath.com/2014/07/dog-cat-and-rabbit-puzzle29.html

 

[wabbitslayer]

cat + dog + bunny = 3