John and Anna bought some eBook readers. John bought 15 eBook readers less than Anna did. Unfortunately, John lost 3 eBook readers. If Anna bought 50 eBook readers, how many eBook readers do they have altogether? Give the rationale and then the answer.
Let's think step by step. John bought 50 - 15 = 35 eBook readers. John has 35 - 3 = 32 eBook readers after losing some. Together they have 50 + 32 = 82 eBook readers.. The answer is: 82.

Malcolm is trying to find the fastest walk to school and is currently comparing two routes. In the first route, he walks for 6 minutes uphill, walks for twice this amount of time along a path, then finishes the journey in a third of the time it took to walk the first two stages. In the second route, he walks along a flat path for 14 minutes, then finishes the walk in twice this amount of time. In minutes, how much longer was the second route compared with the first? Give the rationale and then the answer.
Let's think step by step. In the first route, Malcolm spends 6 minutes * 2 = 12 minutes walking along the path. So in total, the first two stages of this route take him 6 + 12 = 18 minutes. This means the final part of the journey took him 18 / 3 = 6 minutes. Therefore, the total time it takes to walk the first route is 18 + 6 = 24 minutes. In the second route, the second stage takes him 14 * 2 = 28 minutes. So the second route takes a total of 28 + 14 = 42 minutes to walk. The second route therefore takes an extra 42 minutes for the second route – 24 minutes for the first route = 18 minutes.. The answer is: 18.

Ned is an explosives specialist racing to deactivate a time bomb on the top floor of a building. The building has twenty flights of stairs to the top floor, and Ned can run up one flight of stairs in eleven seconds. The time bomb has 72 seconds left on the timer, and Ned has spent 165 seconds running up the stairs. How many seconds will Ned have to diffuse the bomb when he reaches it? Give the rationale and then the answer.
Let's think step by step. Ned has gone up 165 / 11 = 15 flights of stairs. Thus, he has 20 - 15 = 5 flights of stairs left to run up. He will spend 5 * 11 = 55 seconds running up the remaining stairs to the bomb. Therefore, he will have 72 - 55 = 17 seconds to defuse the bomb.. The answer is: 17.