Activities 4B


Student A


Puzzle 1 answer You turn on the first switch for a minute. Then you turn on the second switch and leave it on. You go down to the basement. If the light is on the right switch is number 2. If the bulb is off but warm, it is switch number 1. If the bulb is not on or warm, it is switch number 3.


Puzzle 2 answer You throw the ball up in the air.


Student B


Puzzle 1 answer The baby was on the ground floor of the building when he/she fell out of the window.


Puzzle 2 answer Just before leaving for your friend’s house, you wind the grandfather clock to a random time, 9 a.m., for example. Although this is not the right time, the clock can now be used to measure time. As soon as you arrive at your friend’s house, you look at the time on his clock. Let’s say the time is 7.15. Before leaving the next morning, you look at the clock again. Let’s say the time is now 10.15 (15 hours later). You walk home at the same speed you walked to your friend’s house yesterday. When you arrive home, your clock reads 12.40. By subtracting the time you set it to when you left (9.00) from the current time (12.40) you know that you have been gone for 15 hours and 40 minutes. You spent 15 hours at your friend’s house, so that means you spent 40 minutes walking. Since you walked at the same speed both ways, it took you 20 minutes to walk back home from your friend’s house. So the correct time to set the clock to would therefore be 10.35 (10.15 the time he left his friend’s house + 20 minutes (the time it took him to walk home) = 10.35).


178


English for the 21st


Century • Activities


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