Tilly needs to sell 100 bags at $10 per bag to make $300 in profit. How much did she buy each bag for? Give the rationale and then the answer.
Let's think step by step. Tilly will make 100 x $10 = $1000 in total. She has spent $1000 - $300 = $700 on 100 bags. Each bag cost Tilly $700 / 100 = $7.. The answer is: 7.

Tammy has 10 orange trees from which she can pick 12 oranges each day. Tammy sells 6-packs of oranges for $2. How much money will Tammy have earned after 3 weeks if she sells all her oranges? Give the rationale and then the answer.
Let's think step by step. Tammy picks 10 trees x 12 oranges / tree = 120 oranges per day. Tammy sells 120 oranges / day / 6 oranges / pack = 20 6 - packs of oranges a day. Tammy sells 20 packs / day x 7 days / week = 140 6 - packs a week. In 3 weeks Tammy sells 140 packs / week x 3 weeks = 420 6 - packs. Tammy makes 420 packs x $2 / pack = $840.. The answer is: 840.

There are four lamps in Valerie's room. All of them are burnt out, so she needs to buy new light bulbs. She needs 3 small light bulbs and 1 large light bulb. She has $60 to spend. If small light bulbs cost $8 and large light bulbs cost $12, how much money will Valerie have left over? Give the rationale and then the answer.
Let's think step by step. She will spend 3 * $8 = $24 on small light bulbs. In total she will spend $24 + $12 = $36 on the 4 light bulbs. She will have $60 - $36 = $24 left over.. The answer is: 24.