Part A:
20% of 65 is 13 (0.2 * 65 = 13)
So to increase by 20% would be 65 + 13 = 78 pizzas for the day
Part B:
If they sold 60 then the percentage sold would be
60/65 = 0.923 = 92.3%
To find the increase or decrease subtract 100% from the given percentage
92.3 - 100 = -7.7%
So there was a 7.7% decrease in the number of pizzas sold.
