The gummy bears cost 10 * 2 = $20. The chocolate chips cost 5 * 20 = $100. The total cost for these two is 100 + 20 = $120. The chocolate bars in total cost 150 - 120 = $30. A single chocolate bar costs 30 / 10 = $3.
The answer: 3
Reverse engineering the question: Jessica is having a sweet tooth and bought 10 chocolate bars, 10 packs of gummy bears, and 20 bags of chocolate chips. Her total rang up to $150. If the cost of a pack of gummy bears is $2 and a bag of chocolate chips costs $5, how much does 1 chocolate bar cost?

A kilogram of chicken costs $6 - $2 = $4. Three kilograms of chicken cost $4 x 3 = $12. So, a 3 - kilogram of chicken and a kilogram of pork cost $12 + $6 = $18.
The answer: 18
Reverse engineering the question: A kilogram of pork costs $6 while a kilogram of chicken costs $2 less. How much will a 3-kilogram of chicken and a kilogram of pork cost?

Donaldsons pay $15 / hour = 15 * 7 = $105. The Mercks pay $18 / hour = 18 * 6 = $108. The Hilles pay $20 / hour = 20 * 3 = 60. The total amount Layla earned is 105 + 108 + 60 = 273. Layla earned $273 for babysitting.
The answer: 273
Reverse engineering the question: The Donaldsons pay $15 per hour for babysitting. The Merck family pays $18 per hour and the Hille family pays $20 per hour for babysitting. Layla babysat for the Donaldsons for 7 hours, the Merck family for 6 hours and the Hille family for 3 hours. How many dollars did Layla earn babysitting?

She strength trains 3 * 1 = 3 hours a week. She does boxing training 4 * 1.5 = 6 hours a week. So she trains a total of 3 + 6 = 9 hours a week.
The answer: 9
Reverse engineering the question:
Kat decides she wants to start a boxing career. She gets a gym membership and spends 1 hour in the gym 3 times a week doing strength training. She also trained at the boxing gym 4 times a week for 1.5 hours. How many hours a week does she train?