Brain Teasers
Total Odds
All of the odd numbers from 1 to 999 are added together.
What is the total?
What is the total?
Answer
250,000 (1 + 999) + (3 + 997) + . .(etc) . . . . + (499 + 501)Hide Answer Show Answer
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Comments
I don't believe it. I've come out of chat to show him and this is the first teaser he tries!!!
This is a simple Arithmetic progression. If a is the first term, d the common progression, n the number of terms, l the last term, and s the sum of n terms, then:
n = ((l-a)/d) + 1
and s =(n/2)(a+l)
thus, n = ((999-1)/2)+1 = 500
and s = (500/2)(1+999) = 250,000
n = ((l-a)/d) + 1
and s =(n/2)(a+l)
thus, n = ((999-1)/2)+1 = 500
and s = (500/2)(1+999) = 250,000
Exactly what I would have said _rab... only I would have sounded dumber ;P.
Just wondering when simple maths problems crossed into being teasers?
I just did 500^2 = 250000. The sum of the first n odd numbers is n^2.
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