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
