plzz answer....urgent maths ques
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last digit of 17 to the power of 18 is 1
last digit of 18 to the power of 19 is 8
last digit of 19 to the power of 20 is 9
= 1+8+9 = 9+9 = 18
last digit is 8
therefore answer is (d)
hope it help you
yachi2429:
but how do u know that last digit of 17 to the power 18 is 1??
by doing multiplication
but it's very long process...how to do it in xms?
my trick
is
I'll do like this, in 17 and power 18 I'll take last digits 7 and 8 means I'll multiply 7 into 8times
but then 7×8 is 56...then how last digit is 1???
arey! 7 x 7 x 7 x 7 x 7 x 7 x 7 x 7
ok..thnx
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