ACT Math : Data Analysis
Study concepts, example questions & explanations for ACT Math
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Example Questions
Example Question #1 : Statistics
Ashley scored 80, 80, 83, 85, 90, and 77 on her tests this semester. If she wants an average of 85 on all her tests, which would she have to score on her final test?
None of the other answers.
95
85
100
97
100
One can set up an equation for the average test score. 85=(80+80+83+85+90+77+x)/7.
Solving for x gives 100.
Example Question #1 : How To Find Arithmetic Mean
An olympic athlete has just completed a four mile run. His average time was 6 minutes per mile. If he ran the first and last mile in 5 minutes, and the other 2 were the same time as each other, what was the average time for the 2 miles in the middle?
5 minutes per mile
6 minutes per mile
Not enough information given
7 minutes per mile
14 minutes per mile
7 minutes per mile
The total time spent by the athlete was 24 minutes, if two of the miles took 10 minutes, then the other two took 14.
14/2 yields an average of 7 miles per minute
Example Question #1 : How To Find Arithmetic Mean
On the chart above, what was the class average for Exam 2? Round to 1 decimal point.
81.0
83.1
87.4
79.9
84.9
79.9
Average = (Sum of Grades) / (# of Grades)
= (85+93+65+70+90+72+65+86+93) / 9
= 719 / 9 = 79.9
Example Question #1 : How To Find Arithmetic Mean
Anthony makes $4,000 a month as a bartender 10 months of the year, and for 2 months, he works in a jazz club where he makes $6,000 a month.
What is Anthony's average monthly salary in a year?
In a year, Anthony makes $4,000 x 10 = $40,000
and an additional $6,000 x 2 = $12,000
totaling $52,000
The average monthly salary would be 52,000 ÷ 12 = 4,333
Example Question #11 : Arithmetic Mean
Janice, Candice, Sharon, and Helen have an average height of 65 inches. Janice is the shortest at 55 inches, and Helen is the tallest at 70 inches. What is the average height of Candice and Sharon?
68 inches
62.5 inches
65 inches
63.5 inches
67.5 inches
67.5 inches
First we find the average height for Janice and Helen, (55 + 70)/2 = 62.5. The average of the height for Candice and Sharon must complement this to achieve the overall average of 65. We can solve for their average by doing (62.5 + x)/2 = 65.
Solving this equation yields an average height of 67.5 inches.
Example Question #12 : Arithmetic Mean
Susan got a job at a store folding the display clothes. If she folds shirts during her whole eight-hour shift, except for her thirty-minute lunch break, Susan can fold 180 shirts. How long does it take her to fold one shirt?
250 seconds
2.5 seconds
25 seconds
160 seconds
150 seconds
150 seconds
First you convert hours to minutes by multiplying 8 by 60, giving you 480 minutes. You then subtract her 30 minute lunch break, leaving you with 450 minutes. Then divide this by 180 shirts, giving you 2.5 minutes per shirt. Based on the available answer choices, you then multiply by 60 again to get the time in seconds, 150.
Example Question #11 : Statistics
Sam earned $8/hour working three eight-hour shifts, Monday through Wednesday, at her waitressing job, and earned $9.75/hour tutoring five hours a day, Friday through Sunday. Approximately, what were her daily average earnings?
$59
$58
$48
$49
$56
$56
First you multiply $8 by the eight-hour shift. Sam worked at her waitressing job, making $64. Then multiply that by the three days that she worked, making $192. You then multiply the $9.75 Sam made per hour by the five hours she worked by the three days she worked. This gives you $146.25. Add this to the earnings from her waitressing job, giving you $338.25. Divide this by the 6 days she worked, resulting in $56.38 a day.
Example Question #21 : Data Analysis
Hannah travels 321 miles on 12 gallons of gas. What is her mileage? Round to the nearest mile per gallon.
23 mpg
35 mpg
27 mpg
25 mpg
18 mpg
27 mpg
This is a division problem: 321 miles ÷ 12 gallons = 26.75 miles per gallon, which rounds to 27 mpg.
Example Question #2735 : Act Math
Derek's golf scores for 3 days were 77, 79, and 73. If his 4-day average was a 74, what was his score on the fourth day?
67
71
70
52
67
(77 + 79 + 73 + x)/4 = 74
Solving for x yields 67.
Example Question #22 : Data Analysis
After four tests, Nick has an average of 88; what score does he need to have on the fifth test to raise his average to a 90?
98
88
90
100
87
98
To have an average of 90, Nick has to have 450 points after 5 tests; with an average of 88 after 4 tests he has 352 points, which means that he needs a 98 on the fifth test to reach 450 points.
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