A mail carrier randomly inspects every 20th letter being mailed. Out of 600 letters in the sample, 3 were open. There were 18,000 letters being mailed. Make an inference about the number of all the letters being mailed that were open.

The function c(n) below relates the number of bushels of apples picked at a pick-your-own orchard to the final cost for the apples. it takes as input the number of bushels of apples picked after paying an entry fee to an orchard and returns as output and returns as output the cost of the apples (in dollars)c(n) = 15n + 30which equation below represents the inverse function n(c), which takes the cost of the apples as input and returns the number of bushels picked as output