There are bicycles and cars in the parking lot. The number of bicycles is three times that of cars. There are 150 wheels for the two kinds of cars. How many bicycles and cars are there respectively? Don't use the X method, thank you

The number of bicycles is three times that of cars, and each bicycle wheel is only half that of cars. Therefore, the number of bicycles' wheels is 3 ÷ 2 = 1.5 times that of cars. Proportional distribution: then the bicycle wheels are: 150 x 1.5 / (1 + 1.5) = 90. Bicycles 90 ÷ 2 = 45

There are 32 tricycles and bicycles in the shed, and the wheels of tricycles are 4 less than those of bicycles. How many tricycles and bicycles are there in the shed Don't equation

If there are x tricycles, there are 32-x bicycles
2（32-x）-3x=4
64-5x=4
5x=60
x=15
There are 32-15 = 17 tricycles
A: there are 17 tricycles and 15 bicycles

Each signpost is 100 meters away. It takes 5 seconds for the train to go from the first signpost to the second signpost and 9 seconds from the first signpost to the third signpost,

This problem only needs to know: the formula of uniformly accelerated linear motion s = VT + at ^ 2 / 2. Let the speed (i.e. initial speed) of the train passing through the first sign be V and the acceleration be a. it takes 5 seconds for the train from the first sign to the second sign (it can be seen that the distance is 100 meters), with 100m = V * 5S + A * 5S * 5S / 2

The train with a speed of 18 m / s stops moving 15 seconds after braking. Calculate the acceleration of the train

(0-18)÷15 =

The train is v = 18m / s. The driver found that there is a train with v = 8m / s running in the same direction 50m ahead,

The speed of the rear train relative to the front train is 10m / S;
According to V ^ 2 = 2As:
a=2s/v^2=2*50/10^2=1m/s^2
The braking acceleration shall be at least 1m / S ^ 2

The circumference of a semicircle is 10:28. What is its area?

10.28 / (2 + 3.14) = 2, area 2 square times 3.14 = 12.56

There are bicycles and cars in the parking lot. The number of bicycles is three times that of cars. There are 150 wheels for the two kinds of cars. How many bicycles and cars are there respectively? Don't use the X method, thank you