What is the 25th even integer?
You could write the first twenty five of them and see.
Or you could count them on your fingers to 25, but
that's probably not what your teacher wanted you to
do. I'm guessing you are studying sequences.
2,4,6...
is an arithmetic sequence, the nth term, an, is
given by the formula
an = a1 + (n-1)d
where a1 = the first term and n = the number of term.
Here n = 25, so we want to find a25. The common
difference between even integers is 2, so d = 2.
The first term is 2, so a1 = 2.
an = a1 + (n-1)d
a25 = 2 + (25-1)(2)
a25 = 2 + (24)(2)
a25 = 2 + 48
a25 = 50
I'll bet you could have guessed it would be
twice 25, couldn't you?
Edwin