Answer:
Natalie bought 500 apples at $0.40 each, then she pays $0.40 500 times, this means that the total cost of the 500 apples is:
Cost = 500*$0.40 = $200
Now she threw away n apples from the 500 apples, then the number of apples that she has now is:
apples = 500 - n
And she sells the remaining apples for $0.70 each.
a) The amount that she gets by selling the apples is:
Revenue = (500 - n)*$0.70
b) We know that she did not make a loss, then the revenue must be larger than the cost, this means that:
cost ≤ revenue
$200 ≤ (500 - n)*$0.70
c) We need to solve the inequality for n.
$200 ≤ (500 - n)*$0.70
$200/$0.70 ≤ (500 - n)
285.7 ≤ 500 - n
n + 285.7 ≤ 500
n ≤ 500 - 285.7
n ≤ 214.3
Then the maximum value of n must be equal or smaller than 214.3
And n is a whole number, then we can conclude that the maximum number of rotten apples can be 214.