The reciprocal would be 9/7 because a reciprocal is when you flip a fraction and put the denominator as the numerator and vice versa.
You could use the function:
f(x)=30+2x
100=30+2x
In which lets say he rode 3 rides. Plug in 3 for x.
100=30+2(3)
Then Multiply
100=30+6
Then combine 30 and 6 to get 36.
Then you can subtract 36 from 100 to get
$64 left over.
Answer:

Step-by-step explanation:
We have that

and

This implies that;

and

Now find and expresion for

Which is




Answer:
The awnser is 4.472135955