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Xiao Ming went for an outing from place a to place B by bike. He had planned to arrive in 8 hours. When he reached 90 kilometers of the whole journey, his bike broke down and the speed was slower than planned Please tell us the reason. If it's an equation, don't be the answer directly It's OK to say why "90 / (8-2) = 15 km" Please finish by 7:00 on April 20, Xiao Ming traveled from place a to place B by bike. He had planned to arrive in 8 hours. When he reached 90 kilometers of the whole journey, his bike broke down and the speed was 1 / 5 slower than the plan. As a result, he arrived 30 minutes later than the original plan. The original plan was to go more than one hour
In the remaining distance after 90 km, the speed ratio is 4:5, then the time ratio is 5:4
30 ÷ (5-4) × 4 = 120 minutes = 2 hours
8-2 = 6 hours
90 △ 6 = 15 km
When the speed of a ship in still water is XKM / h and the water flow speed is 1.5km/h, suppose that the distance between a and B is SKM. If the ship goes downstream from a to B, and then upstream from B to a, the time and average speed of a round trip of the ship are expressed by algebraic formula
Time: S / (x-1.5) + S / (x + 1.5)
Average velocity: 2S / (s / (x-1.5) + S / (x + 1.5)) = (x-2.25) / X
If the speed of the ship in still water is XKM / h and the water speed is YKM / h, what is the speed of the ship downstream and upstream?
Primary school students, you go with the water x + y, go against the water X-Y. ha ha, you have nothing to do when you are full
A person takes a ship down from a to B, and then up to C, taking a ship for 3 hours. It is known that the speed of the ship in still water is 8 km, and the current speed is 2 km per hour. If a and C are 2 km apart, find the distance between a and B
Let AB distance be X
x/（8+2）+（x-2）/（8-2）=3
x/10+x/6-1/3=3
8x/30=10/3
x=100/8
X = 12.5km
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