posted by Gav on .
Amy bought some stationary from a bookstore. The total cost of 3 files A,B,C was $5.60 more than the total cost of 4staples. A cost $1.90 less than each of the other 2files. B cost $4.20 more than each staple. Find the cost of C
$X = Cost of B.
$X = Cost of C.
X -!.90 = Cost of A.
X - 4.20 = Cost of each staple.
X + X + (X-1.90) = 4(X-4.20) + 5.60,
3x - 1.90 = 4x-16.80 + 5.60,
3x - 4x = -16.80 + 5.60 + 1.90 = -9.30,
-x = -9.30,
X = $9.30. = Cost of B.
X = $9.30 = Cost of C.
X-1.90 = 9.30 - 1.90 = $7.40=Cost of A.