Sales at a local ice cream shop went 80% in 5 years. if 12,000 ice cream cones were sold in the current year find the number of ice cream cones sound in 5 years

First:  a little editing is needed.

"Sales at a local ice cream shop went 80% in 5 years. If 12,000 ice cream cones were sold in the current year find the number of ice cream cones sound in 5 years" should be "Sales at a local ice cream shop increased by 80% over 5 years. If 12,000 ice cream cones were sold in the current year find the number of ice cream cones sold in 5 years."

What y ou need to do here is to multiply "12,000 ice cream cones" by 1.80, which will produce a result including the original 12,000 cones PLUS 80% more cones:

1.80(12,000 cones) = 21,600 cones.