In this case, we get 41.4 grams of potassium.

Remember, on the earlier problem, we found that we had 55.26%

of potassium by mass in potassium phosphate.

Now we can write a relationship with that percentage and

say 55.26 grams of potassium in 100 grams of K3PO4.

Now that we have this information,

we can use this to actually figure out the grams of just the potassium.

So we have 75.0 grams of K3PO4, and

I need to make sure grams of K3PO4 is in the numer, in the denominator.

So, we have 100 grams of K3PO4 on the bottom,

and we have 55.26 grams of potassium on top.

Now, our grams of potassium phosphate cancelled with our grams of

potassium phosphate.

The value we're left with is the 41.4 grams of potassium.

Here we saw the percentage was a little more then half, and

we see that the mass we get, the 41.4, is a little more then half of

our original 75 gram sample, so this seems to be a reasonable answer.