Question 195048
let  b = base  price  (cost)
let n = number  of  pieces
.
1) b-20 =3n
.
2) b+30 = 3.25 n
.
subtract  (1)  from (2)
.
  50 = .25 n
.
n= 200  pieces
.
subst  into (1)  b-20 = 3(200) = 600
.
  b=620 R  ,,,,,
.
checking
1) 620 - 20 = 3 * 200
600 = 600,,,,ok
2) 620 +30 = 3.25 * 200
  650 = 650 ,,,, ok