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

Answer:

127

Step-by-step 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: $S_n=\frac{a_1(1-r^n)}{(1-r)}$

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

and a = First term = 1

⇒ $S_n= \frac{1\times(1-2^7)}{(1-2)} \\\Rightarrow S_n=\frac{(1-128)}{-1}\\ \Rightarrow S_n=127$