Question

Mike and John split the cost of a $270 car trip. Mike pays $20 more than John. How much did John pay?
I solved it as 20x+x=270
I'm not sure if it's correct, can I please get an explanation
Ms. Sue
Why did you multiply 20 times x?

x + x + 20 = 270

2x = 250

x = 125

Mike paid $125.