MATH 1030-004, Quiz 2 Solution
Spring 2014
1. (4 pts) John’s weekly take-home pay (after taxes) is $675. If he pays 23% of his gross pay (before
taxes) in tax, what is his gross pay?
$675 = (1 − 0.23) · x ⇒ x =
$675
= $876.62.
0.77
2. Express the first number as a percentage of the second.
(a) (2 pt) 220 men at a conference with 430 people.
220
= 0.5116 = 51.16%.
430
(b) (2 pt) 145 Subarus in a parking lot with 436 cars.
145
= 0.3326 = 33.26%.
436
3. In the past four decades, the five-year survival rate for all forms of cancer increased from 36% to
63%. What is
(a) (2 pt) the absolute change?
Absolute Change = 63 − 36 = 27 percentage points.
(b) (2 pt) the relative (percentage) change (in terms of a percentage)?
Relative Change =
1
27%
= 0.75 = 75%.
36%
4. (4 pts) Write each of the following numbers in scientific notation.
(a) 0.011 = 1.1 · 10−2
(b) 225, 500 = 2.255 · 105
(c) 400.51 = 4.0051 · 102
(d) 0.001002 = 1.002 · 10−3
5. (Extra Credit: 4 pts) Find the scale ratio for the map where 1 foot on the map represents 250
meters on the ground. (1 m = 3.28 ft.)
250 m ·
3.28 ft
= 820 ft.
1m
Therefore, the scale ratio is 1 : 820, or 1 to 820.
2