Question

A new shopping mall is gaining in popularity every day since it open the number of shoppers is 20% more than the numbers of shoppers the day before the total numbers of shoppers over the first four days is 671

Answer 1

Answer: the number of shoppers on the first day is 125

Step-by-step explanation:

The number of shoppers is 20% more than the numbers of shoppers the day before. It means that the number of shoppers is increasing in geometric progression. The formula for determining the sum of n terms, Sn of a geometric sequence is expressed as

Sn = (ar^n - 1)/(r - 1)

Where

n represents the number of term in the sequence.

a represents the first term in the sequence.

r represents the common ratio.

From the information given,

r = 1 + 20/100 = 1.2

n = 4(first 4 days)

S4 = 671

Therefore, the expression for the first 4 days is

671 = (a × 1.2^(4) - 1)/1.2 - 1

671 = (a × 1.2^(4) - 1)/0.2

671 = 1.0736a/0.2

671 = 5.368a

a = 671/5.368

a = 125