What mistake did Farah make in this experiment? Farah conducted the following experiment to check whether fabrics of different colours take different times to dry. She took one piece each of red, white and blue cotton. They were all of the same size and quality. She wet each piece with the same amount of water and hung them from spring balances near a fan as shown above. She noted the weight of each piece of cotton. She then put the fan on and noted the weight of each piece of cotton at the end of every two minutes. The weight of all the pieces of cotton decreased as water evaporated from the them.

You have two photos of a person walking. one shows the person at the corner of third and main streets, the other shows the person at the corner of tenth and main streets. there are lampposts at every corner in this town, and the first picture shows it to be 10: 32: 00 exactly. the second picture shows it to be 10: 49: 30. you know three facts: (1) all of the clocks are synchronized; (2) there are exactly 12 equal-sized blocks per kilometer in this town; and (3) the streets that cross main in this area are numbered consecutively, with no interruptions. what is the person’s average speed in kilometers per hour?