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27 Aug 2023, 11:00
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D
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
25%
(medium)
Question Stats:
78% (01:52) correct
22%
(02:12)
wrong
based on 144
sessions
History
Date
Time
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Not Attempted Yet
What is the difference of the sum from 26 to 50, inclusive and the sum from 1 to 25, inclusive?
(A) 500
(B) 525
(C) 600
(D) 625
(E) 800
(A) 500
(B) 525
(C) 600
(D) 625
(E) 800
27 Aug 2023, 12:29
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Bunuel
The sum of all integers from 1 to 50, both inclusive = \(\frac{50 * 51 }{2}\)
The sum of all integers from 1 to 25, both inclusive = \(\frac{25 * 26 }{2}\)
The sum of all integers from 26 to 50, both inclusive = \(\frac{50 * 51 }{2} - \frac{25 * 26 }{2}\)
Question -
What is the difference of the sum from 26 to 50, inclusive and the sum from 1 to 25, inclusive
\(\frac{50 * 51 }{2} - \frac{25 * 26 }{2} - \frac{25 * 26 }{2}\)
\((25 * 51) - (25*13) - (25*13)\)
\(25 * (51 - 26)\)
\(25 * 25\)
\(625\)
Option D
31 Aug 2023, 09:41
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26+27+28+29+....+50
-1-2-3-4........-25
There are 25 terms in each sum
And difference between every ith term is 25
So difference between their sums is 25*25= 625.
So D
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-1-2-3-4........-25
There are 25 terms in each sum
And difference between every ith term is 25
So difference between their sums is 25*25= 625.
So D
Posted from my mobile device
