Answer:
2,800 Books to be the same.
I can't see the graph but let's use logic
hmm, more than 10 cubic feet of topsoil so the first and 2nd options are wrong
let's ee the costs
3rd option
10*1=10
2*12=24
10+24=34 and 34<50, that is fine
4th option
3*10=30
2*12=24
30+24=54
54>50, nope, that is over cost
answer is 3rd one
the one with 1 cubic yard compost and 12 cubic yard topsoil
If the top is $48 and it is 60% off you will multiply the cost by the decimal form of the sale percentage: 48*0.60= $28.80. This is the amount she will save and I think is the answer you are looking for.
If there is a follow up question asking for the final cost of the top you would find that by subtracting the amount saved from the original cost: 48.00-28.80=$19.20.
I would say c or d. but since its multiple choice, its ok to guess sometimes.