A school ordered $600 worth of lightbulb. Some of the lightbulbs cost $1 and the others cost $2 each. If twice as many $1 bulbs as $2 bulbs were ordered, how many lightbulbs were ordered altogether?
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Page 598 #13
A school ordered $600 worth of lightbulb. Some of the lightbulbs cost $1 and the others cost $2 each. If twice as many $1 bulbs as $2 bulbs were ordered, how many lightbulbs were ordered altogether?
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Page 598 #13
1)$\displaystyle 600=2x+y$
2)$\displaystyle y=2x$
then, on 1...
$\displaystyle 600-2x=2x$
$\displaystyle 600=4x$
$\displaystyle x=600/4$
$\displaystyle x=150$
then on 2:
$\displaystyle y=2(150)$
$\displaystyle y=300$
so, total bulbs:
$\displaystyle x+y=300+150$
$\displaystyle x+y=450$