The speed of a car is 70 km / h. now measured by a meter which is 5 minutes slower per hour, the speed of the car is () The original speed of the car was 70km / h, that is, 70km / h. now it is measured with a meter that is 5 minutes slower than an hour. That is to say, although the normal time is 1 hour and the car runs 70km, it only takes 55 minutes, that is, 11 / 12 hours Then the speed of this car is 70 / (11 / 12) = 840 / 11 km / h How to understand the 11 / 12 inside

The speed of a car is 70 km / h. now measured by a meter which is 5 minutes slower per hour, the speed of the car is () The original speed of the car was 70km / h, that is, 70km / h. now it is measured with a meter that is 5 minutes slower than an hour. That is to say, although the normal time is 1 hour and the car runs 70km, it only takes 55 minutes, that is, 11 / 12 hours Then the speed of this car is 70 / (11 / 12) = 840 / 11 km / h How to understand the 11 / 12 inside

60 minutes = 1 hour
55 minutes is 11 / 12 of 60 minutes, that is, 55 minutes is 11 / 12 of an hour

The speed of a car is 77 kilometers per hour. There is a watch that is 30 seconds fast per hour. When you use this watch, what is the speed of the car?

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Every hour is 30 seconds fast, two hours is one minute fast, 120 hours is one hour fast, the distance of 120 hours actually shows 121 hours, so the measured speed of the car is 120 * 77 / 121 = 76.364 km / h

The speed of a car is 60 kilometers per hour. Now, with a meter which is 0.5 minutes slower per hour, the speed of the car is 60 kilometers per hour

The problem is the speed of the car
With a 0.5 minute slow meter, the actual running time is 59.5 minutes when the meter runs for 1 hour, and the actual running time is 60 minutes when the meter shows 60 minutes. The speed of the car is 60 km / h, that is, 1 km per minute, 60.5 km in 60.5 minutes, and 60.5 km per hour