Ms. Hatcher taught 20 x 2 = 40 fourth graders for the day. She taught 20 / 2 = 10 fifth - graders as a substitute teacher for the day. Therefore, she taught 20 + 40 + 10 = 70 students for the day.
The answer: 70
Reverse engineering the question: Ms. Hatcher teaches 20 third-graders and a number of fourth-graders that is twice the number of third-graders. Her co-teacher asked her to substitute for her fifth-grade class that has half as many students as the number of third-graders. How many students did Ms. Hatcher teach for the day?
Reasoning and answer: They cost 2.25 * 100 = 225 cents each. At the bulk rate, they are 24 / 12 = 2 dollar each. They cost 2 * 100 = 200 cents each. 225 - 200 = 25 cents are saved per bagel.
The answer: 25
What was the question?
Question: The bagels cost $2.25 each, or a dozen for $24. How much is saved, per bagel, in cents, by buying a dozen at a time?
Carlton has 2 * 3 = 6 sweater vests. He can wear each sweater vest with different 3 button - up shirts, so Carlton has 3 * 6 = 18 outfits.
The answer: 18
Reverse engineering the question: Carlton wears an assortment of sweater vests and button-up shirts. He has twice as many sweater vests as button-up shirts and considers each unique combination of vest and shirt to be an outfit. He owns three button-up shirts. How many outfits does Carlton have?
Reasoning and answer: There are 9 - 4 = 5 blue pens left in the jar. There are 21 - 7 = 14 black pens left in the jar. There are 5 + 14 + 6 = 25 pens left in the jar.
The answer: 25
What was the question?
Question: A jar contains 9 blue pens, 21 black pens, and 6 red pens. Four blue pens are removed and then seven black pens are removed. How many pens are left in the jar?
There will be 18 members and she wants to allow 2 biscuits per member so that's 18 * 2 = 36 biscuits. Her biscuit recipe yields 9 biscuits and she needs to make 36 biscuits so she needs to make 36 / 9 = 4 batches of biscuits. 1 batch of biscuits uses 1 1 / 4 cup flour and she needs to make 4 batches so she will use 1.25 * 4 = 5 cups of flour.
The answer: 5
Reverse engineering the question: Lady Bird uses 1 1/4 cup flour to make 9 biscuits. She's hosting this month's Junior League club which has 18 members and wants to make sure she allows 2 biscuits per guest. How many cups of flour will Lady Bird need?
The two t - shirts amount to $8 x 2 = $16. The two bags amount to $10 x 2 = $20. So Timothy spent $16 + $20 = $36 for the shirts and bags. He still has $50 - $36 = $14 left to spend for the key chains. With the money, he can buy $14 / $2 = 7 sets of key chains. Therefore, he can buy 7 x 3 = 21 pieces of key chains.
The answer: 21
Reverse engineering the question:
Timothy has $50 to spend at a souvenir shop. He sees some t-shirts that cost $8 each, key chains that sell 3 pieces for $2, and bags that cost $10 each. Timothy buys 2 t-shirts and 2 bags. How many pieces of key chains can he buy with the amount of money he has left?