Answer:
The number of days is 13.
Step-by-step explanation:
It is given that a birds watcher saw 3 blue jays on the first day of his vacation. Each day after that he saw 2 more blue jays than he did on the previous day.
[tex]a_1=3[/tex]
[tex]a_2=a_1+2=3+2=5[/tex]
[tex]a_3=a_2+2=5+2=7[/tex]...
It means the series is
3,5,7,..., 27
The first term of series is 3 and the common differences is 2.
The formula of nth term is
[tex]a_n=a+(n-1)d[/tex]
Substitute [tex]a_n=27[/tex], a=3 and d=2.
[tex]27=3+(n-1)2[/tex]
[tex]27=3+2n-2[/tex]
[tex]27=1+2n[/tex]
[tex]26=2n[/tex]
[tex]n=13[/tex]
Therefore the number of days is 13.
