Math 060 Quiz 1b Answer Key

MATH 060 TTh 1:30-3:35, Room A-107

Name: ____Answer Key___________________________

You may have noticed that the points in this quiz add up to 12 points. Think of it as 2 extra credit points. At the end of the semester, the quizzes in this class will be scaled based on 10 points. All additional points are extra credit. QUIZ 1 September 4, 2008 1. Solve this inequality: (4 points)

2. Solve for y and check your answer: (4 points) 2 (y + 5) = 3 (1 – 4y)

5 (6 – x) < 3x + 6 Solution:

Solution:

Expand everything:

Expand everything: 2y + 10 = 3 – 12y

30 – 5x < 3x + 6 Subtract 6 both sides, then add 5x both sides:

Subtract 10 both sides, then add 12y both sides: 14y = –7

24 < 8x Divide by 8, no change in direction:

Divide by 14: y = – 1/2 ; or: y = –0.5

3<x Or:

x>3

Check: Left side:

2 (–0.5 + 5) = 2 (4.5) = 9

Right side: 3 (1 – 4(–0.5)) = 3 (1+2) = 9 3. Answer the following questions: (4 points) a/

What’s 1½ % of 400?

b/

3% of what is 15?

Solution:

Solution: 1 ½ = 1.5 1 ½ % = 1.5% 1.5% of 400 = 0.015 · 400 = 6

Let x be the amount we’re looking for. Then: (3%) x = 15 Or:

0.03 x = 15 x = 15/0.03 = 500