Question: Baez has 25 marbles. She loses 20% of them one day. Then a friend sees her and gives her double the amount that Baez has after she lost them. How many marbles does Baez end up with?
Answer: She loses 5 marbles because 25 x .2 = 5. She has 20 marbles after this because 25 - 5 = 20. Her friend gives her 40 marbles because 20 x 2 = 40. Adding those marbles to the 20 she had before, she ends up with 40 marbles + 20 marbles = 60 marbles. The answer is 60.

Question: Pete walks backwards three times faster than Susan walks forwards, and Tracy does one-handed cartwheels twice as fast as Susan walks forwards. But Pete can walk on his hands only one quarter the speed that Tracy can do cartwheels. If Pete walks on his hands at 2 miles per hour, how fast can Pete walk backwards, in miles per hour?
Answer: If Pete walks on hands at 1 / 4 what Tracy can do 1 - handed cartwheels, then Tracy can do 1 - handed cartwheels at 2 * 4 = 8 miles per hour. Since Tracy does 1 - handed cartwheels twice the rate of Susan's forward walking, then Susan walks at 8 / 2 = 4 miles per hour. Pete walks backwards 3x faster than Susan walks forward, and thus Pete walks backwards at 4 * 3 = 12 miles per hour. The answer is 12.

Question: Lavinia's daughter is 10 years younger than Katie's daughter. Lavinia's son is 2 times the age of Katie's daughter. If Katie's daughter is 12 years old, how many years older is Lavinia's son than Lavinia's daughter?
Answer: Lavinia's daughter is 12 - 10 = 2 years old. Lavinia's son is 12 * 2 = 24 years old. Lavinia's son is 24 - 2 = 22 years older than Lavinia's daughter. The answer is 22.

Question: Jack will have ten times more handball trophies than Michael has right now in three years. If Michael has 30 trophies right now, and the number of his trophies increases by 100 in three years, what's the total number of trophies they'll have altogether after three years?
Answer:
In three years, Michael will have 30 + 100 = 130 trophies. If Michael has 30 trophies now, Jack will have 10 * 30 = 300 in three years. Altogether, Jack and Michael will have 300 + 130 = 430 handball trophies in three years. The answer is 430.