the 41st term of the sequence 25,27.5,30,32.5... is
we have
a1=25
a2=27.5
a3=30
a4=32.5
a2-a1=27.5-25=2.5
a3-a2=30-27.5=2.5
a4-a3=32.5-30=2.5
This is an aritmetic sequence
where
the common difference is d=2.5
the general formula is equal to
an=a1+d(n-1)
we have
a1=25
d=2.5
substitute
an=25+2.5(n-1)
an=26+2.5n-2.5
an=23.5+2.5n
Find the 41st term
For n=41
substitute
an=23.5+2.5(41)=126
therefore
41st term is 126