Question

find the sum of series 12+14+16 ...220​

Answer 1

Step-by-step explanation:

= 12+14+16+18+20+....+220

= 2+4+6+8+10+12+14+16+18...+220 - (2+4+6+8+10)

= 2(1+2+3+4+5+6+...+110) - 2(1+2+3+4+5)

we know formula of sum of AP = n(n+1)/2

= 2*(110*111)/2 - 2*(5*6)/2

= 12,210 - 30

= 12,180