Differentiating once, we have

Differentiating again,


as needed.
Remember that percent means parts out of 100
x/100
discount is the decrease
so we divide the decrease by the original total and get
100/5775=0.0173
convert to fraction
0.0173/1
make bottom number 100
multiply by 100/100
1.73/100=1.73%
round
2%
Answer:
120 baseball cards
Step-by-step explanation:
15 × 2 = 30
30 + 10 = 40
40 ÷ 1/3 = 40 × 3/1 = 120
Therefore there were 120 cards in the back
<em>I just did the inverse of each process starting from the last step and ending at the first</em>