Solving Graphic Equations

• May 28th 2008, 05:12 PM
noelly_01
Solving Graphic Equations
(Itwasntme) How do you solve this question? Please help me. The weights of two beluga whales and 3 orca whales add up to 36,000 pounds and one of the orcas add up to 13,000 lbs. Using this info only... How much do the beluga's weigh? How much so the orcas weigh?
• May 28th 2008, 05:35 PM
Jonboy
Are you sure you don't mean: the 2 orca whales add up to 13,000 lbs?

Because I'm getting an odd answer...

Let $b$ be the weight of a beluga whale

Let $o$ be the weight of an orca whale

You know: "The weights of two beluga whales and 3 orca whales add up to 36,000 pounds"

So: $2b + 3o = 36,000$

And: "...one of the orcas add up to 13,000 lbs."

So $o = 13,000$

We have 2 orca whales, so their weight is two times the weight of one.
So its weight is: $2(13,000) = 26,000\,lbs$.

Use the value of $o$ to get the weight of one beluga whale.

$2b + 3(13,000) = 36,000$

$2b + 39,000 = 36,000$

$2b = -3,000$

$b = -1,500$

A negative weight? I don't see how... ?
• May 28th 2008, 06:01 PM
noelly_01
Quote:

Originally Posted by Jonboy
Are you sure you don't mean: the 2 orca whales add up to 13,000 lbs?

Because I'm getting an odd answer...

Let $b$ be the weight of a beluga whale

Let $o$ be the weight of an orca whale

You know: "The weights of two beluga whales and 3 orca whales add up to 36,000 pounds"

So: $2b + 3o = 36,000$

And: "...one of the orcas add up to 13,000 lbs."

So $o = 13,000$

We have 2 orca whales, so their weight is two times the weight of one.
So its weight is: $2(13,000) = 26,000\,lbs$.

Use the value of $o$ to get the weight of one beluga whale.

$2b + 3(13,000) = 36,000$

$2b + 39,000 = 36,000$

$2b = -3,000$

$b = -1,500$

A negative weight? I don't see how... ?

Wouldn't it be
2b + 3o = 36,000
o = 13,000
2o (13,000)=26,000
2b + 26,000=36,000
Does this make any sense to you? at least up to here?
• May 28th 2008, 06:05 PM
noelly_01
Quote:

Originally Posted by noelly_01
Wouldn't it be
2b + 3o = 36,000
o = 13,000
2o (13,000)=26,000
2b + 26,000=36,000
Does this make any sense to you? at least up to here?

2(5000) + 26,000 = 36,000
Is this OK or am I more confused?
• May 28th 2008, 10:04 PM
mr fantastic
Quote:

Originally Posted by noelly_01
(Itwasntme) How do you solve this question? Please help me. The weights of two beluga whales and 3 orca whales add up to 36,000 pounds and one of the orcas add up to 13,000 lbs. Using this info only... How much do the beluga's weigh? How much so the orcas weigh?

Please do NOt ask questions in LiveChat. That's what the Math Forum is for.