When one number is negative and the other is positive.
5 because 20:6 is the car to motorcycle.
6:15 is the motorcycle to van.
20÷15=5
~JZ
Answer:

Step-by-step explanation:
The given function is
Let

Interchange x and y.

Solve for y,

Divide both sides by 2

Therefore;

Answer:
1. 8/$12=21/$x then cross multiply.
2. 1/$1.5, we're looking for cost so $1 is more reasonable
3. $31.5
Step-by-step explanation:
12x 21/ 8 = 31.5
800 is 10 times as much as 80