SOLUTION: The number of visitors to a website in the first week is 50. The number of visitors each week is double the number of visitors the previous week. What is the total number of visit

Sum of the 8 first terms of the geometric progression with the first term 50 and the common ratio of 2:


  50 + 5*2 + 50*2^2 + . . . + 50*2^7 = 


= 50*(1 + 2 + 2^2 + . . . + 2^7) = 50*(2^8-1) = 50*(256-1) = 50*255 = 12750.