Follow the directions and show your work. im offering 15pts (way more than its worth) and brainliest answer. quick

I'll take this challenge since I'm not feeling lazy for once....   x would represent Gavin and y would represent Seiji.  

a.     

b.   I will solve your system using substitution.    
  
Step 1: Solve  for x
(add -y for both sides)

Step 2: substitute  for x in 


(simplify both sides of the equation)
(add -425 to both sides)
 

y=200
step 3: substitute 200 for y in 





c.   Already answered with the picture that is attached.

d.   Gavin earned 225 dollars while Seiji earned 200 dollars.