Question

The sum of all integers between 200 and 800,witch is divisible by 9

Answer 1

Answer:

Step-by-step explanation:

first term and last term which is divisible by 9 in between 200 and 800 are

a = 207

l = 792

l = a + (n-1) d

792 = 207 + (n-1)9

(792 - 207) / 9 = n-1

585 / 9 = n-1

65 = n-1

n=66

S = n/2(a+l)

  = 66/2(207+792)

  = 33*999

  = 33(1000-1)

  = 33000-33

  =  32967