Question

A jar of jelly beans that weigh 4.25 ounces costs 2.89. what is the cost of one ounce of jelly

Answer 1

You have:
Cost in dollars --> $2.89
Total ounces --> 4.25

But you want to know the per unit cost for *1* ounce.

You have the right method. You want cost ($) per ounce so put the price over the amount in ounces.
2.89 / 4.25 = x / 1

If you notice, since the denominator is 1, this is simply:
x = 2.89 / 4.25

So the unit cost is just $2.89 divided by the number of ounces (4.25).

Plug that into your calculator and you get:
0.68

That's in dollars. So if you want it in cents, move the decimal point 2 places to the right.

Answer:
$0.68 per ounce
or
68 cents per ounce