I beat the system yay
Gill Bates (09-11-2014)
I was technically the first one that got this... I posted the answer in the other thread but you edited your damn message... -_-
Code:
Gill Bates (09-11-2014)
Das true. @Predator,your answer is invalid,Invis got it lolz.
Invis. (09-11-2014)
Invis. (09-11-2014)
Code:
ahmedbomba (09-14-2014)
Alright, since you boys are done playing let me show you the real way we do things around here.
Suppose we have a list here for all the times the 7 Appears in the last decimal place (7, X7, XX7, example : 147) Lets call the list U.
U = {7, 17, 27, 37,..., 877}
The equation for any n is U_{n} = 7 + 10n. so:
877 = 7 + 10n
870 = 10n
n = 87 so the number 7 appears 87 times in the last decimal place.
1 - Thus, U_{total} = 87
___________________________________
Now , suppose we have another list for all the times the number 7 Appears in the second decimal place (7X, X7X, example : 70, 570) lets call this list U'
U' = {70, 170, 270, 370, ... , 870}
The equation for any n for this list would be : U^{'}_{n} = 70 + 100n
so:
870 = 70 + 100n
800 = 100n
n = 8 so the number 7 appears 9 times in the second decimal place.
2 - Thus, U'_{total} = 9 ( the reason it is 9 is because we didn't add the first number (n = 0) )
___________________________________
Now we need another list to find out how many times the 7 appears in the second decimal place (7X, X7Y, example : 76)
Lets call this list Z.
Z_{n} = {70, 71, 72,..., 79} =======> it appears 10 times for every 100 in the U' list
3 - So..., Z_{total} = 9 * U'_{total} = 90
___________________________________
Now lets see how many times the number 7 Appears in the first decimal place.. well this is easy, 7XX
the only number that has 7 in the first place in the range 1 - 877 is 700 so. it appears 1 time only.
But how many times does the number 7 appear from 700 to 799 ?? well thats also easy, it appears 100 times !
SO, the total times the number 7 appears is :
U_{total} + Z_{total} + 100*1 = 87 + 90 + 99 = 276
The number 7 appears 276 times from 1 to 877.
Okay now @iCudi , you better have me rewarded because i wasted valuable time figuring this out... so you better 10/10 me. bich.
Last edited by somewhatpro; 09-14-2014 at 01:32 PM.
ahmedbomba (09-14-2014)
YESS! bitch, see that shit?.. @Predator i got a cookie son.