Luke is planning a trip to London and wants to see how long it will take him to travel there. He decides that he will take a bus to the town center, walk for 15 minutes to the train center, wait twice this long for the train to arrive, and then take the 6-hour train ride to London. If Luke’s entire trip takes him 8 hours, how many minutes does his bus ride take? Give the rationale and then the answer.
Let's think step by step. Removing the time of the train ride from the journey shows that his trip to get on the train took him 8 hours – 6 hours = 2 hours. Converting this time into minutes shows that getting to the train took 2 hours * 60 minutes / hour = 120 minutes. Waiting for the train to arrive took twice as long as his walk, so 15 minutes * 2 = 30 minutes. This means that his bus ride must have taken 120 minutes – 30 minutes - 15 minutes = 75 minutes.. The answer is: 75.

Francine has five full boxes of crayons and 5 loose crayons, and her friend has 27 loose crayons. They need to put all of their loose crayons in a box. How many more boxes do they need if Francine has a total of 85 crayons? Give the rationale and then the answer.
Let's think step by step. Francine has 85 - 5 = 80 crayons in total that are in the boxes. Thus, each box of crayons is filled with 80 / 5 = 16 crayons. A total of 5 + 27 = 32 crayons need to be placed in the boxes. Therefore, they still need 32 / 16 = 2 boxes for the loose crayons.. The answer is: 2.

Ken can do 20 sit-ups without stopping. Nathan can do twice as many, and Bob can do half the number of Ken and Nathan's combined sit-ups. How many more sit-ups can Bob do compared to Ken? Give the rationale and then the answer.
Let's think step by step. Nathan can do 20 x 2 = 40 sit ups. Ken and Nathan's combined number is 20 + 40 = 60 sit - ups. Bob can do 60 / 2 = 30 sit - ups. Bob can do 30 - 20 = 10 more sit - ups than Ken.. The answer is: 10.