$21 I believe (it's 1 am where I am so I'm not 100% sure but I think it's correct)
20+2x=3x subtract 2x from both sides
20=x after 20 miles the total cost for both companies will be the same
PROOF
20+2(20)=3(20)
20+40=60
60=60
The answer to the problem is 10 :)
Answer:

Step-by-step explanation:
Using PEMDAS rule
Parentheses, Exponents , Multiplication, Division, Addition, Subtraction
![\sf{4 [ 3 + 3(5 - 1) ]}](https://tex.z-dn.net/?f=%20%5Csf%7B4%20%5B%203%20%2B%203%285%20-%201%29%20%5D%7D)
Subtract 1 from 5
![\longrightarrow{ \sf{4 [3 + 3 \times 4 ]}}](https://tex.z-dn.net/?f=%20%5Clongrightarrow%7B%20%5Csf%7B4%20%5B3%20%2B%203%20%5Ctimes%204%20%20%5D%7D%7D)
Multiply the numbers : 3 and 4
![\longrightarrow{ \sf{4 [ 3 + 12 ]}}](https://tex.z-dn.net/?f=%20%5Clongrightarrow%7B%20%5Csf%7B4%20%5B%203%20%2B%2012%20%20%5D%7D%7D)
Add the numbers : 3 and 12

Multiply the numbers : 4 and 15

Hope I helped!
Best regards! :D
The practical domain would be all integers 10 to 50.<span />