Step-by-step explanation:
always remember some basic principles when dealing with percentages :
100% is the whole
1% = 100%/100
n% = n×1% = n×100%/100
therefore, n% of an amount m is n/100 × m.
like 25% = 25/100 × m = 0.25 × m
so, now it should be very easy :
the 25% discount of $80 is
0.25×80
the amount deducted by (= after) the discount is
80 - 0.25×80
which is actually 0.75×80
a markup is added into the total cost incurred by the producer of a good or service in order to cover the costs of doing business and create a profit. so, a markup of 40% is simply again
0.40×80
and the sale price including (= after) the markup is then
80 + 0.40×80
