Jawabanmu

Jawaban paling cerdas!
2014-04-25T17:27:31+07:00
Barisan aritmetikanya sbb :
105 + 110 + 115 + ... + 295 didapat a = 105 , b = 5 dan Un = 295
Un  = a + (n - 1)b
295 = 105 + (n - 1)5
295 - 105 = 5n - 5
190 = 5n - 5
195 = 5n
n = 195/5
   = 39
Sn = (n/2)(a + Un)
S39 = (39/2)(5 + 295)
      = 39(150)
      = 5850
1 5 1
2014-04-25T17:47:08+07:00
(300-100):5
200:5
40
jadi,ada 40 bilangan