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by Christina Trbovich » Sat Sep 27, 2008 4:24 am
Any leads?


What is the sum of the integers from -190 to 195, inclusive?

A. 0
B. 5
C. 375
D. 875
E. 965
:oops:

Its weird... I have read a few different equations of figuring out the following sum. I thought something like [(first term-last term)/2] +1 *(first term+last term).
When I did that, I got 9655 and the answer is 965. hermmm..
hoping for 750!
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by LSB » Sat Sep 27, 2008 4:56 am
the Q is asking what the value of 191+192+193+194+195 is
(The sum of all numbers in the range of -190 to 190 is equal to zero)

So to the real question: what is the sum of the numbers between 191 and 195 inclusive


(191+195)/2 = 193 (this is the average of the numbers between 191 and 195 inclusive)

193 * 5 = 965 --> Ans E

You have to understand the average formulae:

If you have a set with equal intervals between each element of the set (in our case 1) ... then the average of the set is equal to

(Min # + Max #) / 2

If you have the average of the set, then the total sum of all elements of the set is

Average * # of elements in the set
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