3.4+Paying+Bills+and+Counting+Profits+0910

Emma Jacoby Math7E September 23, 2009

Problem 3.4 Big Idea: Paying bills and counting profits Essential question: Sidney was a bit nervous about the partners using her rough estimates to make such decisions. She decided to look more closely at the company’s costs and the resulting profit. She found that although the trip would bring in 350$ from each rider, it would have operating costs of 30$ for each person’s bike rental, 125$ for each person’s food and camp posts, and 700$ per tour to rent the van for the trip. Sidney put her estimated cost and income data in a table.

Notes:

A. Number of customers Income Bike rental Food and camp costs Van rental Total cost Profit 1 $350 $30 $125 $700 $855 -$505 2 $700 $60 $250 $700 $1010 -$310 3 $1050 $90 $375 $700 $1165 -$115 4 $1400 $120 $500 $700 $1320 $80 5 $1750 $150 $625 $700 $1475 $275

6 $2100 $180 $750 $700 $1630 $470 7 $2450 $210 $875 $700 $1785 $665 8 $2800 $240 $1000 $700 $1940 $860 9 $3150 $170 $1125 $700 $2095 $1055 10 $3500 $300 $1250 $700 $2250 $1250 …..25 $8750 $750 $3125 $700 $4575 $4175

B. As the number of costumers increases the income column also increases because more customers pay for the tour. In the income column of the table there is a pattern. Every customer pays $350 dollars so all you need to do to calculate the amount of money a certain number of customers would pay is to multiply the number of customers by 350.

C. Like the Income column, the total cost increases with the number of customers because more bikes, food and camp posts are needed. To calculate the total cost for any number of customers you need to add the Bike rental, the van rental and the food and camp costs of that number of customers together.

D. For five customers the profit is 275 dollars, for 10 customers the profit is 1250 dollars and for 25 customers the profit is 4175 dollars.

Problem 4.2 follow up

1. Other patterns of change in the table are in the bike rental where it increases by 30$ with every customer, and in the food and camp posts where the pattern increases with every customer by $125. 2. The least number of customers needed to make a profit is 5 customers. 3. To make the tour worthwhile the students need about 9 customers.