Final answer:
The percentage of pastrami sandwiches sold is found by dividing the number of pastrami sandwiches by the total number of sandwiches and then multiplying by 100 to get a percentage. The correct equation and solution are 36 / 90 = p, which gives p = 40%.
Step-by-step explanation:
The student is asking how to write and solve an equation to find the percentage of pastrami sandwiches sold in a deli out of the total number of sandwiches sold.
The correct equation to represent this situation is 36 / 90 = p, where p is the percentage (in decimal form) of pastrami sandwiches sold out of the total. To solve for p, divide 36 by 90, which gives p = 0.4. To convert this decimal to a percentage, multiply by 100, resulting in p = 40%. Therefore, 40% of the sandwiches sold were pastrami.