CTET Solved Paper - CTET September 2015
is
107. The additive inverse of S, where S = 1-2+3-4+5-6+7-8+....+49-50, is
- Option : D
- Explanation : (D) S = 1-2+3-4+5-6+7-8+...+49-50
S = (1+3+5+7+...+49)+(-2-4-6-....-50)
⇒ Sum of first n odd numbers = n2
Sum of first n even numbers = n(n+1)
∴ S = (25)2 - (25)(26)
S = 625 - 650
S = -25
∴ Additive inverse of (-25) is -(-25) = 25
is
, where a = 2, b = 3 and c = 0, is
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