Final answer:
The original number of apples the seller had is 700, and 25% of 80 is 20.
Step-by-step explanation:
The student is tasked with finding the original number of apples the fruit seller had before selling some of them and with calculating 25% of 80. To solve the first problem, the student needs to understand that if the fruit seller is left with 420 apples after selling 40%, then 420 apples represent 60% of the original number. Using a simple percentage formula, the student can find the original number:
60% of original number = 420 apples
original number = 420 apples / 0.60
original number = 700 apples
For the second problem, the student needs to calculate what 25% of 80 is:
25% of 80 = 0.25 × 80 = 20
So, 25% of 80 is 20.