Answer:
0.40d
d - 0.60d
Step-by-step explanation:
d - 0.60
This doesn't work because it wants 60% 0.60 without the percent is a decimal number, and is not 60% of d.
100% - 60% = 40%
0.40d works because it is multiplying 0.40 and d which is also 40%.
d - 0.60d works because it is multiplying 0.60 and d which is also 60% and then subtract it from d.
0.60d doesn't work because it want the discounted price not the discount.
1 - 0.60d doesn't work because we don't know that d = 1, so it is subtracting the discount from 1 not d.
