501 Questions To Master GED Test Mathematics_pag356

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501 Questions to Master the GED® Mathematical Reasoning Test
 445. The correct answer is 1.75 hours. The mean is the average. To 
find the average of four numbers, find the sum of the numbers and 
divide by 4. Michael spent 2 hours doing homework on Monday, 
1.5 hours on Tuesday, 2.5 hours on Wednesday, and 1 hour on 
Thursday. The sum of this time is 7 hours (2 + 1.5 + 2.5 + 1 = 7). 
Next, divide 7 by 4 (7 ÷ 4 = 1.75). The mean is 1.75 hours.
 446. The correct answer is 89. The median of a data set is always the 
very middle number when they are arranged in increasing order. 
With an odd number of data points, finding the median is easy. 
However, when you have an even number of data points, there are 
two middle numbers. The median is then the average of those two 
middle numbers.
 To find the missing score, we first need to order the data points 
from least to greatest: 
 79, 84, 84, 92, 92, 92, 94
 The problem states that the missing point in the data set is between 
84 and 92. So, let’s let x represent the missing score and add it to 
our chronological list: 
 79, 84, 84, x, 92, 92, 92, 94
 The middle two numbers are x and 92.
 The problem also states that the average of these two numbers is 
90.5. Let’s set up an equation and then solve for x:
 x + 92_____
2 = 90.5
 2(x + 92_____
2 ) = (90.5) × 2
 x + 92 = 181
 –92 –92
 x = 89
 The missing grade is 89.
501_MathQues_09_313-362.indd 341 7/26/17 4:04 PM