Modeling Business Decisions and Market OutcomesFall 2004
SM222
ALGEBRA and EXCEL QuizAnswers
Name: ______
Section Time and Professor: ______
You have 30 minutes to complete this quiz. Write your answers to all but Question 10 in the following table (Write the letter or letters only for 7, 8 & 9.) Use the graph provided to answer question 10. Seven or more correct answers constitute a passing score.
Question / 1 / 2 / 3 / 4 / 5 / 6 / 7 / 8 / 9ANSWER / Q change:
-35 / MPG=
14.93 / x=4.125
y=2.625 / x=1000 / number:
22 / Alan:
$128,000
Bonnie:
$120,000 / c / a and f / c, e, f
1)Assume the equation of the quantity Q demanded is Q = 200 – 7 P where P is the price.
The price is originally $10. If price increases by 5, how much does Q change? -7 * 5 = -35
2) I drove exactly 220 miles on $28.00 of gasoline. The cost of one gallon was $1.90. How many miles per gallon (MPG) did I get? 220mi/$28 * $1.90/1 gal = 14.93 mi/gal
3) At what value of x and y do the following two lines intersect (if at all)?
X + 3y = 12 10x – 2y = 36 One easy way to solve this is by substituting:
x = 12 – 3y so 10(12 – 3y)-2y =36 then solve for y=2.625; x=12-3(2.625)=4.125
4) If log x = 3(where log is to the base 10),then x = ?? By definition: 10 log x = x So x =103=1000
5) If ln y = 6 and ln x = 8, what number is ln (y x2 ) ?= ln y + 2*ln x = 6 + 2*8=22
6) Alan and Bonnie work at Trouble Inc. This year, Alan’s salary grew 5% but Bonnie’s grew only 3%. These increases in Alan’s and Bonnie’s salaries will amount to a total extra cost of $10,000 for Trouble Inc. this year. Last year, Bonnie made $8,000 less than Alan did. How much did Alan and Bonnie make last year? (Ignore taxes, benefits…)
Two equations in two unknowns,: .05A+.03B=10 and A-B=8
where A=Alan’s last year salary in ‘000 and B=Bonnie’s last year salary in ‘000
Substituting A=8+B .05(8+B)+.03B=10 so B=120 A=8+120=128
7) Point A is (7,1). Point B is (3,9). (The first number in each parenthesis represents the x-value, the second the y-value) What is the slope of the line passing through these two points?
Slope= (9-1) / (3-7) = 8 / -4 = - 2
a. 2
b. 1/2
c. -2
d. -1/2
e. none of the above
8) I need to calculate semester grades for a class of 10 students. Each student took two midterms – each worth 30% -- and one final worth 40%. Using the spreadsheet of grades below, I want to put a formula for semester numerical grade for John Doe into cell E2. I want to write the formula so that I can copy it (using “copy” or ctl-C) into E3-E11 to calculate the other students’ grades. Which of these formulas will accomplish this? THERE CAN BE MORE THAN ONE CORRECT ANSWER.
a. =B2*$G$2+C2*$G$2+D2*$G$3
b. =$B$2*G$2+$C$2*G$2+$D$2*G$3
c. =$B2*$G2+$C2*$G2+$D2*$G3
d. =B$2*G$2+C$2*G$2+D$2*G$3
e. =$B$2*G2+$C$2*G2+$D$2*G3
f. =$B2*$G$2+$C2*$G$2+$D2*$G$3
A / B / C / D / E / F / G1 / Midterm 1 / Midterm 2 / Final / Overall grade / weights
2 / John Doe / 100 / 90 / 88 / each midterm / 0.3
3 / Risto Dow / 80 / 75 / 62 / final / 0.4
4 / Melissa Frank / 90 / 86 / 100
5 / Milton Friedman / 100 / 90 / 95
6 / Susan Jones / 89 / 94 / 92
7 / George Larson / 88 / 85 / 90
8 / Lisa Mitchell / 95 / 100 / 89
9 / Bob Nelson / 93 / 90 / 96
10 / Janine Stone / 80 / 90 / 100
11 / Hu Xian / 77 / 84 / 86
9) In the above spreadsheet, I want to put the average grade on the final in cell D12. Which of these formulas will accomplish this? THERE CAN BE MORE THAN ONE CORRECT ANSWER.
a. =AVG(D2:D11 )
b. =AVERAGE(D2+D3+D4+D5+D6+D7+D8+D9+D10+D11)
c. =(1/10)*SUM(D2,D3,D4,D5,D6,D7,D8,D9,D10,D11)
d. =AVG(D2,D3,D4,D5,D6,D7,D8,D9,D10,D11)
e. =AVERAGE(D2:D11)
f. =SUM(D2+D3+D4+D5+D6+D7+D8+D9+D10+D11)/10
10) On the graph below, draw the line represented by the equation y = 8–6x