Suppose a chain letter scheme works like this. You would receive a letter with a list of 5 names, send a penny to the person at the top of the list, cross that name out, and add your name to the bottom of the list. Suppose you received one of these letters today and sent it to 6 other persons, each of whom sent it to 6 other persons, each of whom sent it to 6 others, and so on. How many letters would have your name on the list?

How much money would you receive if the chain were not broken?

The number of chocolate chips in an 18-ounce bag of chocolate chip cookies is approximately normally distributed with a mean of 1252 chips and standard deviation 129 chips. (a) what is the probability that a randomly selected bag contains between 1100 and 1500 chocolate chips, inclusive? (b) what is the probability that a randomly selected bag contains fewer than 1125 chocolate chips? (c) what proportion of bags contains more than 1225 chocolate chips? (d) what is the percentile rank of a bag that contains 1425 chocolate chips?

X+y=-4 x-y=2 use elimination with adding and subtraction

Awater tank holds 18000 gallons. how long will it take for the water level to reach 6000 gallons if the water is used at anaverage rate of 450 gallons per day