Question

Markus receives dollar bills from his grandfather for one week on the first day he received $1 on the second day he received $2 on the third day he received $4 and on the fourth day he received $8 if this continues how much money will Marcos have by the end of the week

Answer 1

Marcos will have $127 by the end of the week

Answer 2

127

Explanation:

It gas geometric sequence,

We has a sequence: 1, 2, 4, 8, 16, 32, 64.

It can be solved by two method either sum these digits individually or use formula of sum of geometric sequence

We have formula:
`S_n=(a_1(1-r^n))/((1-r))`

Here r = Common Ratio = 2 ÷ 1 = 4÷2 = 2

and a = First term = 1

⇒
`S_n= (1*(1-2^7))/((1-2)) \\\Rightarrow S_n=((1-128))/(-1)\\ \Rightarrow S_n=127`