yu hav arithmatik sequens with start=2, step=4, number terms=10 . . . for all such sequenses, last number=start+(n-1)*step . . . averaej=(start+last)/2 . . . sum=n*averaej . . . yu want a sequens av 5 number that sum tu 100???????? . . . averaej=100/5=20 . . . averaej=(start+last)/2 =20 . . . so (start+last)=2*20=40 . . . last=start+(n-1)*step..... so (last-start)=(n-1)*step=4*4=16 . . . (if step=4) . . . add: (last+start) +(last-start)=2*last =40+16=56 . . . thus, last=56/2=28 . . . start=last-16=12 . . . sequens=12, 16, 20, 24, 28