Answer:
f(n + 1) = f(n) + 20
Explanation:
Let f(x) equals their pay at every hour of X
Where x is the number of hours, then if we go with the trend where f(1)=110, f(2)=130 f(3)=150 f(4)=170 then would see that as they are working every hour they have their pay increased by $20, from f(1)=110+ $20 gives us f(2)=130 and that is after an hour then we can say
1 hour work=$20
Then additional 1hour+ n= $20 + n
Hence,f(n+1)=f(n)+20