Lizzy: Frank wants to buy a new lamp for his bedroom. The cost of the cheapest lamp is $20, and the most expensive in the store is 3 times more expensive. How much money would Frank have remaining, if he currently has $90, and he buys the most expensive lamp available?.
Me: Hmmm, let me think. I think this is the detailed solution:
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The most expensive lamp cost 20 * 3 = $60. So if Frank would pay for that lamp, he would leave himself with 90 - 60 = $30. Final answer: 30.
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