7^1+7^2+7^3+...........+7^2015 find out how many numbers present which unit place contain 3 ?	Choose the correct choice from the following options:	A) 504	B) 505	C) 506	D) 507	E) 508
7^3,7^7,7^11,7^15,7^19.........7^2015 contains last digit=3.   Now,we see   3,7,11,15....2015 are in 504P   tn=a+(n-1)d   2015=3+(n-1)4   2015=3+4n-4   4n=2016   n=504   504NSWER:504
<result>A</result>
7^1+7^2+7^3+...........+7^2015 find out how many numbers present which unit place contain 3 ?