Final answer:
To calculate the tip, convert the 20% tip rate to decimal by dividing it by 100. Then, multiply this decimal by the total bill amount. Then, they can multiply this decimal by the total bill amount of $52.50. 20% of $52.50 = 0.20 x $52.50 = $10.50
Step-by-step explanation:
To find out how much tip they should leave, they need to calculate 20% of the total bill amount. To do this, they can first convert the percentage to a decimal by dividing it by 100. So, 20% becomes 0.20. Then, they can multiply this decimal by the total bill amount of $52.50. 20% of $52.50 = 0.20 x $52.50 = $10.50