Question

Colby loves to download new music. He originally had 34 songs but plans to purchase 6 new songs each week. He wants to know how many songs he will have after 100 weeks. Which equation should he use?
a100 = 34 + 6(100 + 1)
a100 = 34 + 6(100 − 1)
a100 = 100 + 6(34 − 1)
a100 = 100 + 6(34 + 1)

Answer 1

Week    # of Songs
1            34
2            34 + 6
3            34 + 6*2
4            34 + 6*3
...
n            34 + 6*(n - 1)

100        34 + 6* (100 - 1)

Answer: second option