Question

Determine the 20th term of the sequence 1,4,7,...

Answer 1

Each term goes up by 3 so if n is the nth term and y is the value y=3n but the first term is 1 not 3 so
y=3n-2
The 20th term is n=20 so
y= 58

Answer 2

It is 58
That's the 20th number in the sequence since each term is 3 more than the last number. An easy way to do this is multiply 19 times 3 because there are 19 terms after one. Then multiply by 3 because each term is 3 more than the last term. After you do 19 x 3 you get 57 right? Then add 57 to 1, the first term, to get 58.