Respuesta :

hello : 
250/500=500/1000=1/2  ..(commmon ratio) of  geoemtric  sequence
the sum is : S= a1(1-r^n)/(1-r)
a1 = 1000   and     n = 5         r = 1/2
S5 = 1000(1-(1/2)^5)(1-1/2)
S5 = calculate ........