snookers lumber can convert logs into either lumber of plywood. in a given day, the mill turns out three times as many units of plywood as lumber. it makes a profit of $20 on a unit of lumber and $50 on a unit of plywood. how many of each unit must be produced and sold in order to make a profit of $17170?

Question

snookers lumber must produce and sell ?
___ units of lumber

and

___ units of plywood to make a profit of $17170

Answer 1

"... the mill turns out three times as many units of plywood as lumber"

If L stands for the units of lumber, then 3L is the number of units of plywood.

"it makes a profit of $20 on a unit of lumber and $50 on a unit of plywood"

$20*L is the profit on lumber, and
$50*(3L) is the profit on plywood.

Total profit = $17170 = $20*L + $50*(3L)
Solve for L.

Answer 2

See also:
http://www.jiskha.com/display.cgi?id=1246350411
for more explanation.