Question 735197
What we know: Gas Price on Monday $3.51, 22% decrease on Wednesday from Monday price, 14% increase on Friday from Wednesday price. 

What we want: Cost to fill 11 gallon tank on Friday

(1) Calculate 22% of Mondays price:
{{{.22*3.51 = .77}}}
NOTE: this is the price decrease from Monday to Wednesday $0.77

(2) Subtract this figure from Monday's price:
{{{3.51-0.77 = 2.74}}}
NOTE: This is the price on Wednesday $2.74

(3) Calculate 14% of Wednesday's price:
{{{.14*2.74 = .38}}}
NOTE: this is the price increase from Wednesday to Friday $0.38

(4) Add this figure to Wednesday's price:
{{{2.74 + 0.38 = 3.12}}}
Note this is Friday's price $3.12

(5) Calculate the cost of filling your 11 gallon tank:
{{{3.12*11 = 34.32}}}

Thus it will cost $34.32 to fill an 11 gallon tank on Friday at this particular convenient store.

Likewise, if we filled up on Wednesday it would cost us $30.14 and on Monday it would cost $38.61