2. To find the sales tax, multiply the cost of the sneakers by the tax rate: $87.21 * 4.2% = $87.21 * 0.042 = $3.66. So Cole will pay $3.66 in sales tax. The correct answer is A.
3. To find the percent decrease, first find the difference in earnings: $4,500 - $2,921 = $1,579. Then, divide that by the original amount and multiply by 100: ($1,579 / $4,500) * 100 = 35%. The correct answer is D.
4. To find the discount, multiply the price by the discount rate: $56 * 40% = $56 * 0.4 = $22.40. Then subtract the discount from the original price: $56 - $22.40 = $33.60. Jane paid $60, so her change is: $60 - $33.60 = $26.40. The correct answer is C.