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 $\displaystyle b$ be the weight of a beluga whale

Let $\displaystyle o$ 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: $\displaystyle 2b + 3o = 36,000$

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

So $\displaystyle o = 13,000$

We have 2 orca whales, so their weight is two times the weight of one.

So its weight is: $\displaystyle 2(13,000) = 26,000\,lbs$.

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

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

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

$\displaystyle 2b = -3,000$

$\displaystyle b = -1,500$

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