Question 1123094
a. 25% of 140 =$35 so $105 left, and 20% or that is $21, so $84 is the cost.
b. f(C)=[(140-(140*0.25))]*0.80, here instead of subtracting the 20% discount, one can multiply by 80% of the cost.
c. 20% of $140 is $28 and $112 is left.  Take 25% of that and get $28, and the cost is $84.
d. f(C)=0.75{140-(0.20*140)]