wow awesum question archana...................cant find a clue..............hw d heck shud v start????
(A):22225555+55552222 is divisible by 7.
(R):xn-an is divisible by x-a,n is even or odd and xn+an is divisible by x+a if n is odd.
answer is A.............jus tell me how is reason explainin the assertion part??
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10 Answers
hehe......gini pig i m ...not genius.....wud have solved this question if i were.......
ya kamal............she alreadyy told that itz A but she is asking for the explanation..dude tell the explanation .........
now,
2222 ≡ 3(mod7)
5555 ≡ 4(mod7)
it can be written as
(22225555+45555)+(55552222 - 42222)+(42222 - 45555)
22225555+45555 is divisible by 7 as 5555 is odd and 2226(=2222+4) is divisible by7
similarly
55552222 - 42222 is divisible by 7 as 5551 (5555-4) is divisible by7
now , 45555=10241111
and 42222 = 161111
now,
1024(mod7) = 16(mod7) = 2
therefore,
10241111(mod7) = 161111(mod7) = 23(370)+1(mod7) = 2
so we have,
45555 = 7m+2 and
42222 = 7n+2 (for some m,n belongs to integers)
so (42222 - 45555) = 7(n-m) = 7p
so we have
(22225555+45555)+(55552222 - 42222)+(42222 - 45555) is divisible by 7
and statement 2 correctly explains statement 1
This first one arjit asked me the day he was here :)
I hope you got the solution above :)