Answer:
The students got 3 signatures on first day.
Explanation:
We are given the following in the question:
The number of signatures students get each day is 3 times as many as the day before.
Thus, the number of signatures form a geometric progression with common ratio 3.
![r = 3](https://img.qammunity.org/2021/formulas/mathematics/high-school/kwwq49ll8zkn8qws185659ws63jkrec9lx.png)
Number of signatures on sixth day =
![3^6](https://img.qammunity.org/2021/formulas/mathematics/middle-school/knxkh9mjt40nmlnryjx2nfnmhcm5erheig.png)
term in a geometric progression is given by:
![a_n = ar^(n-1)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/ms8kio35bpqd8h4ztji6u795rry9u4kuo9.png)
where a is the first term of the series and r is the common ratio.
![a_6 = 3^6\\3^6 = ar^(5)\\3^6 = a(3)^5\\a = 3](https://img.qammunity.org/2021/formulas/mathematics/middle-school/ww7ow8nyjlfarddf1vq4saki1kn2h0oz7u.png)
Thus, the first term of geometric progression is 3.
Thus, the students got 3 signatures on first day.