TestMagic Forums - View Single Post - Sum of even numbers:-

raunekk · 07-23-2008, 06:53 PM

i had read d solution for this previously also..

Take numbers 1 to 7
Even numbers = 2+4+6=12= 3*4

Take number s 1 to 10
Even numbers = 2+4+6+8= 20 = 4*5

Take 1 to 15
even numbers = 2+4+6+8+10+12+14= 56 = 7*8

Thus if sum is 79*80 ( n (n+1))

Ans is 79

07-23-2008, 06:53 PM	#8 (permalink)
raunekk Eager! Join Date: Jun 2008 Posts: 68	i had read d solution for this previously also.. Take numbers 1 to 7 Even numbers = 2+4+6=12= 34 Take number s 1 to 10 Even numbers = 2+4+6+8= 20 = 45 Take 1 to 15 even numbers = 2+4+6+8+10+12+14= 56 = 78 Thus if sum is 7980 ( n (n+1)) Ans is 79