Pete's sales are x.
Bill's sales are y.
x-5/x=308 given in problem
x-.2x =308 substitute value of y for x
.8x/.8 =308/.8 divide both sides by .8
x=308/.8 or 375 division
Pete's sales are 385;
Bill's sales are one fifth of that: 77
check 385-77-308 given in problem
385/5= 77 given in problem