algebra
posted by julie on .
a jeweler purchased 5 oz of a gold alloy and 20 oz of a silver alloy for a total cost of $540. The next day at the same price per ounce, the jeweler purchased 4 oz of th egold alloy and 25 oz of the silver alloy for a total cost of $450. Find the cost per ounce of the gold and silver alloys.

cost of gold per ounce = x
cost of silver per ounce = y
5x + 20y = 540 > x + 4y = 108
4x + 25y = 450
1st equation times 4
4x + 16y = 432
4x + 25y = 450
subtract them
9y = 18
y = 2
sub into x+4y = 108
x + 8 = 108
x = 100
WOW! $100 per ounce of gold
Quickly tell me where and I will be a millionaire within a few hours, lol