trangle wrote:The sum of the first 50 positive even integers is 2,550. What is the sum of the even integers from 102 to 200 inclusive?
a. 5,100
b. 7,550
c. 10,100
d. 15,500
e. 20,100
OA: B
Sum = (number of integers) * (average of biggest and smallest)
To count the number of evenly spaced integers in a set:
Number of integers = (Biggest - Smallest)/(distance between each successive pair) + 1
The distance between each successive pair of even integers is 2.
Thus, the number of even integers from 102 to 200 = (200-102)/2 + 1 = 50.
Average of biggest and smallest = (200+102)/2 = 151.
Sum = (number of integers) * (average of biggest and smallest) = 50*151 = 7550.
The correct answer is
B.
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