[Question]George donated half his monthly income to charity and spent $20 from the other half on groceries. If he now has $100 left, how much was his monthly income?
[Answer]Half his monthly income is $100 + $20 = $120. His monthly income therefore is 2 * $120 = $240. The answer is 240.

[Question]Lydia is planning a road trip with her family and is trying to plan a route. She has 60 liters of fuel and she will use all of this during her trip. She isn't sure how much fuel she is going to use in the first third of the trip but she knows she will need a third of all of her fuel for the second third of the trip, and half this amount for the final third of the trip. How much fuel, in liters, can Lydia use in the first third of the trip?
[Answer]In the second third of the trip, Lydia is going to use 60 liters of fuel / 3 = 20 liters of fuel. In the final third of the trip, she needs half of this amount so she is going to be using 20 liters / 2 = 10 liters of fuel. So in the first third, Lydia used the remaining amount of fuel which is 60 total liters of fuel – 20 liters of fuel in the second third – 10 liters of fuel in the final third = 30 liters of fuel. The answer is 30.

[Question]Barbara went shopping in a supermarket. She bought 5 packs of tuna for $2 each and 4 bottles of water for $1.5 each. In total, she paid $56 for her shopping. How much did Barbara spend on different than the mentioned goods?
[Answer]For the tuna Barbara needed to pay 5 * 2 = $10. For the four bottles of water, she needed to pay 4 * 1.5 = $6. On different goods Barbara spend 56 - 10 - 6 = $40. The answer is 40.

[Question]Jill spends time every day talking to her boyfriend on the phone. The first day of the week she spends 5 minutes on the phone with her boyfriend. Each of the following days she spends twice as much time talking on the phone as the day before. After the 5th day her parents take the phone away from her because she was on it too long. How much time did Jill spend talking to her boyfriend that week?
[Answer]
Jill starts off spending 5 minutes on the phone, and the following day she spends double that 5 minutes for 5 * 2 = 10 minutes. The following day Jill spends double the previous day's total of 10 minutes on the phone, for 10 * 2 = 20 minutes. On the fourth day, Jill spends double the previous day's total of 20 minutes on the phone, for 20 * 2 = 40 minutes. On the fifth and final day, Jill spends double the previous day's total of 40 minutes on the phone, for 40 * 2 = 80 minutes. All told, Jill spends 5 + 10 + 20 + 40 + 80 = 155 minutes on the phone over 5 days. The answer is 155.