Answer
The explicit formula is A(n)=20+4(n-1). After 9 customers buy there are 52 tires.
Work Step by Step
1. The explicit formula is A(n)=20+4(n-1) because every time a customer buys new tires, 4 tires end up in the recycling bin and therefore the number of tires is increasing by 4. Also the first term in the sequence is 20 because A(1) is 20 tires as they started with 16 tires before any customer came.
2. After 9 customers buy there are 52 tires.
To solve this you plug in n=9
A(9)=20+4(9-1)=20+4(8)=20+32=52 tires
