The teacher is handing out note cards to her students. She gave 20 note cards to the first student,

The teacher is handing out note cards to her students. She gave 20 note cards to the first student, 30 note cards to the second student, 40 note cards to the third student, and 50 note cards to the fourth student. If this pattern continues, how many note cards will the teacher give to the fifth student?

• Student 1 has 20
• Student 2 has 30
• Student 3 has 40
• Student 4 has 50

The teacher adds 10 note cards to each student. Or, if we want to put in a sequence formula, we have:
S(n) = 10 + 10n where n is the student number

Simplified, we write this as:
S(n) = 10(1 + n)

The question asks for S(5)
S(5) = 10(1 + 5)
S(5) = 10(6)
S(5) = 60

If we wanted to simply add 10 and not use a sequence formula, we see that S(4) = 50.
So S(5) = S(4) + 10
S(5) = 50 + 10
S(5) = 60