Question

Bob and Alice have designed and created a website for their high school. The first week they had 5 visitors to the site; the second week, they had 10 visitors; and during the third week, they had 20 visitors. If the trend continues, how many visitors can they expect in the fifth week? Explain your answer.

Answer 1

80 visitors

Explanation:

From the above question, we can see that:

The trend is explained using geometric sequence

The formula for Geometric sequence is given as:

an = ar ^n - 1

Where a = first term

r = common ratio

n = number of terms

an = nth term

From the above question, let the number of term be equal to the number of weeks.

First week = First term = 5

Second week = Second term = 10

Third week = Third term = 20

Common ratio = a2/a1 = a3/a2 = 10/5 = 20/10 = 2

We are to find the number of visitors for the Fifth week = fifth term,

Hence:

a5 = 5 × 2^5 - 1

a5 = 5 × 2^4

a5 = 80 visitors

The number of visitors we can expect for the fifth week = 80 visitors