A school ordered $600 worth of lightbulbs. Some of the lightbulbs cost $1 each and the other cost $2 each. if twice as many $1 bulbs as $2 bulbs were ordered, how many lightbulbs were ordered altogether?

Question

anonymous · Answer

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kropot72 · Answer

Let the number of $1 lightbulbs ordered = c
Let the number of $2 lightbulbs ordered = d
Then 2c = d...................(1)
c + 2d = 600.................(2)
Now all you need to do is to substitute the value obtained for d in equation (1) into equation (2) and solve to find c, and from there find d and the total number of lightbulbs. Can you do that?