You tell me if this makes sense to you.
It's 47 years from 1970 to 2017 so you would need to multiply 7% by the 47 years.
So: 0.07x47= 3.29
Now you should add your new price to your original price: $3.29+$0.35= 3.64
So it should cost $3.64 now. Yes that does seem kind of low but that's how you do it.
I hope this helps :)
70 people are in the band
10 flute players
20 trombone players
10 drummers
30 trumpet players