Of course you need to know what "gross margin percentage" means.
Roughly speaking it is the profit as a percentage of sale price.
When a unit costs $1.00 and is sold at $2.50 the excess revenue is $1.50
Although we could express this profit margin as a FRACTION of the sale price,
(so this would be 1.50/2.5 = 3/5), it is usual to state this as a PERCENTAGE.
The gross margin percentage in the original case would be 100 3/5 = 60%
Let cost price be c, sale price be s.
Gross margin percentage g = 100 (s - c)/s
Solving this for sale price s
s = c/[1 - (g/100)]
When unit cost increases $0.25 we have c = 1.25
so s = 1.25[1 - 0.6] = 1.25/0.4 = 3.1
Action needed to maintain the gross margin percentage
is to increase selling price to $3.10
