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Numerical Ability
Number System
The units digit of the sum of the first 86 positive integers (that is 1 + 2 + 3 + ... + 86 ) is
a) 0.0
b) 6
c) 8
d) 1
Read Solution (Total 12)
-
- n(n+1)/2
86*87/2
3*7=21
1 - 10 years agoHelpfull: Yes(23) No(0)
- n(n+1)/2
86*87/2
43*87=3741
so unit digit is 1.. - 10 years agoHelpfull: Yes(4) No(1)
- it will be 1
ans 1 - 10 years agoHelpfull: Yes(3) No(0)
- n(n+1)/2=86(87)/2=3741
unit digit=1 - 10 years agoHelpfull: Yes(1) No(1)
- ye que bhi nhi aata kya.... to phir tcs bhul javo..
- 10 years agoHelpfull: Yes(1) No(0)
- (86*87)/2
than 6*7/2=21
hence unit digit 1 - 10 years agoHelpfull: Yes(1) No(0)
- 1
- 10 years agoHelpfull: Yes(0) No(0)
- n*(n+1)/2
86*87/2 = 3741
so the unit digit = 1 - 10 years agoHelpfull: Yes(0) No(0)
- it obviously should be 1.
sum=n(n+1)/2 86*87/2=last digit of 1
- 10 years agoHelpfull: Yes(0) No(0)
- 1
- 10 years agoHelpfull: Yes(0) No(0)
- ans 1.....
- 10 years agoHelpfull: Yes(0) No(0)
- it is always 1
(215+1)^25/2/215
by bionomial theorm it give one
- 9 years agoHelpfull: Yes(0) No(0)
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