10^2 + 11^2 + 12^2 = 100 + 121 + 144 = 365 13^2 + 14^2 = 169 + 196 = 365 the problem becomes (365 x 2)/365 = 2
-
-
-
My solution : 10²+11²+12²+13²+14² =(10+0)²+(10+1)²+(10+2)²+(10+3)²+(10+4)² =(10²+2*10*0+0²)+(10²+2*10*1+1²)+... =5*10²+2*10*(0+1+2+3+4)+(0²+1²+2²+3²+4²) =5*100+20*10+(0+1+4+9+16) =500+200+30 =730 =2*365
- 1 more reply
New conversation -
-
-
The numerator is (12-2)²+(12-1)²+12²+(12+1)²+(12+2)². When you expand cross terms cancel and you get 5(12²+2). So the fraction simplifies to (12²+2)/73=146/73=2.
-
More symmetry here than expanding at 10, but at 10 the terms are cleaner to add mentally.
End of conversation
New conversation -
-
-
500+21*4+23*3+25*2+27 = 500+84+69+50+27 = 730 => 730/365 = 2
-
- 2 more replies
New conversation -
-
-
This Tweet is unavailable.
-
This Tweet is unavailable.
-
-
-
Find a way, not the answer:|
-
This Tweet is unavailable.
New conversation -
Loading seems to be taking a while.
Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.