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# Math 120 Finite Mathematics

• ###### Sample of what you should know before taking Math 120:
1. Find the equation of the line (in both point-slope form and slope-intercept form) that goes through the points, (2, -1) and (-6, 3) .
• Solution
First, find slope of the line: (using the formula ) Now use either of the given points, say (2, -1) and the slope to first find the equation of the line in point-slope form: Now, solve for  to get the slope-intercept form:  2. You invested \$7000 in two accounts paying 6% and 8% annual interest. If the total interest earned for the year was \$520, how much was invested at each rate?
• Solution
Let x be amount invested at 6% and let  be amount invested at 8%. therefore, Substitute for  in the second equation:    Thus, \$2,000 invested at 6% and \$5,000 invested at 8%.
3. Graph: • Solution
Graph the line and then pick a test point say (0, 0) and substitute into the original inequality ; becomes which is an untrue statement, thus the opposite side of the line is shaded. 4. Solve and round your answer to the nearest hundredth.
• Solution    5. Evaluate • Solution   • ###### Sample of what you will learn in Math 120:
1. Given that and , find • Solution
Finding and by row reduction techniques; and   2. Two fair coins were tossed, and it is known that at least one was a tail. Find the probability that both were tails.
• Solution
Let E be the event of at least one tail and let F be the event of two tails. and so, 3. How many 5-digit zip codes are there that can be read upside down?
• Solution
There are five numbers that can be read upside down, namely zero, one, six, eight, and nine.  So there are zip codes that can be read upside down.
4. A small pizza parlor offers two different types of crusts: New York style and Chicago style; three different pie sizes: small, medium, and large; and ten different toppings.  How many possible four topping pizza pies can be ordered at this pizza parlor?
• Solution
The number of possible pizza pies is obtained by choosing a crust type, a size, and 4 toppings.
So, =1260 different four topping pizza pies can be ordered.
5. Leslie is an athlete who believes that her playing career will last 7 years. To prepare for her future, she deposits \$24,000 at the end of each year for 7 years in an account paying 6% compounded annually. How much will she have on deposit after 7 years?
• Solution
Her yearly payment form an ordinary annuity with periodic payments Since the interest is compounded annually, the interest per period is and the number of periods Using the formula for the future value of an annuity, the amount S that she will have on deposit after 7 years is:  