what is the sum of all even numbers between 99 and 301

• Ans is 20,200
  as,we have sequence from 100,102,...,288,300.
  so a=100,d=2,tn=300,so we have 101 elements,as per formula tn=a+(n-1)d.
  and now sum=n/2(a+l)=101/2(100+300)=20200
• 11 years agoHelpfull: Yes(8) No(1)
• So if the smallest and largest integers are 100 and 300,the mean is 200
  Next, the number of terms. Between 100 and 199, inclusive, for instance,
  there are exactly 100 integers,50 of which are even. If we look at 100 to 200,
  inclusive, there are 51 evens. By the same principle, between 100 and 299,
  inclusive, there are exactly 200 integers, 100 of which are even. Include 300,
  and there are 101.
  Thus, there are 101 terms
  sum, then, is:
  200(101) = 20200(ans)
• 11 years agoHelpfull: Yes(5) No(0)
• n*(n+1)/2
  so n=301-99=202
  202*(202+1)/2
  202*(203)/2=20503
• 10 years agoHelpfull: Yes(0) No(2)