multiply the number of ounces by the price per ounce
Blue jelly beans cost 0.28 per ounce and there are 4 ounces
4 * 0.28 = 1.12
red jelly beans cost 0.55 per ounce and there is 3 ounces
3 *0.55 = 1.65
now add the totals: 1.12 +1.65 = 2.77
this is more than the total they want of 2.20
so it is not reasonable.