SOLUTION: A school has $600 to purchase light bulbs. Light bulbs cost $1.00 and $2.00. The school purchased twice as many $1.00 light bulbs as it did $2.00 light bulbs. How many light bulbs

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Question 43442: A school has $600 to purchase light bulbs. Light bulbs cost $1.00 and $2.00. The school purchased twice as many $1.00 light bulbs as it did $2.00 light bulbs. How many light bulbs were purchased altogether?
I know the answer is 450 (300 $1.00 bulbs and 150 $2.00 bulbs) but I can't figure the equation. I think this may involve two equations?
Answer by psbhowmick(489) (Show Source):
You can put this solution on YOUR website!
Let us suppose that the school purchased 'x' bulbs, each costing $2.
As the school purchased twice as many $1.00 bulbs as it did $2.00 bulbs, so it must have purchased '2x' bulbs, each costing $1.

Cost of all $1 bulbs = $1 x (no. of $1 bulbs purchased) = $ = $2x.
Cost of all $2 bulbs = $2 x (no. of $2 bulbs purchased) = $ = $2x.
Total cost of all bulbs = $2x + $2x = $4x.
Given: total cost of all bulbs = $600.

So, 4x = 600 or x = = 150.

Hence the answer.