A worker is paid

0.07 on the first day,
0.14 on the second day,
$0.28 on the third day, and so on.
How much is the worker paid in total after working for 26 days?

Select one:
a. Between 0 and 1000(FALSE)
b. Between 1000and2 000 000
c. Between 2000000and4 000 000 (FALSE)
d. Over $4 000 000

3 answers

A sequence of numbers each of which is progressively increased by the same factor, in this case, the factor is 7, is known as a geometric time 7 x 26
In your problem, n = 26 (the number of days), so, the total number of
money received for 26-days work would be: A
Sum of a geometric series = a(r^n - 1)/(r - 1)
here a=.07 , r=2 , n = 26

sum = .07(2^26 - 1)/(2-1)
= $4,697,620.41
In this case, the factor is 2, not 7.
So, with a starting value of a = 0.07,
S26 = .07(2^26-1)/(2-1) = 4,697,620.41 or (D)
(C) is correct for the amount paid on the 26th day, not the total