6: the cost of a protein bar increased from $2.50 to $2.80. the percent increase in the $2.80 rate was how much?

The original cost of protein bar = $2.50

The increased cost of protein bar = $2.80

Therefore, the increase in price of the protein bar = $2.80-$2.50 = $0.30 percentage increase = (Difference in price / Original price) x 100

= (0.30/2.50) x100

= (3/25) x100

=3 x 4

=12%