SAT math practice question: Arithmetic Sequences

 
Try the following SAT math practice question (Calculator Permitted) that tests your understanding of arithmetic sequences.

Question(Calculator Permitted):

Aaron is planning to save money every Sunday of the week to buy a car. He will save $\$100$ on the first Sunday of the year. Each Sunday after the first, he will save $\$40$ more than he saved on the preceding Sunday. Which of the following is an expression for the amount of dollars that Aaron would save on the $n$th Sunday of his savings effort?

1. $\quad 80n+20$
2. $\quad 40n+100$
3. $\quad 40n+80$
4. $\quad 40n+60$