How many minutes is 7 / 12 of an hour? How much is 5 / 6 of 3 more than 3 / 5

How many minutes is 7 / 12 of an hour? How much is 5 / 6 of 3 more than 3 / 5

1 h = 60 min, 60 × 7 / 12 = 60 △ 12 × 7 = 35 min
5 / 6 of 3 can be divided into three parts to get 23 3
- minus -
6 5
Pass and share
115 18
——Minus——
30 30
97
——
thirty

1 / 2 of 5 / 6 of 12 is to calculate!

12×5/6×1/2=5

34 △ 7 × (- 1 / 7) and (1 / 3 + 3 / 4-5 / 6) △ (- 1 / 12) should be calculated

34 △ 7 × (- 1 / 7)
= -34×1/7×1/7
= -34/49
=34 out of 49
(1 / 3 + 3 / 4-5 / 6) / (- 1 / 12)
=（1/3+3/4+5/6）÷（-1/12）
=1/3×（-12）-3/4×12-5/6×12
= -4-9-10
= -23

25% of a number is 12 more than 1 / 5 of 80

(80x1/5+12)÷25%
=(16+12)÷1/4
=28x4
=112

The four mixed operations of fraction are the same as (), which are first (), then (), with brackets (), and finally ()

The four mixed operations of fractions are the same as those of integers. They are all calculated first (multiplication and division), then (addition and subtraction), those with brackets (the ones in brackets should be calculated first), and the final result (the scores that can be reduced)

As shown in the figure, the mass of the uniform equilateral right angle bending bar OAB is 2? M, and the angular velocity ω rotates around the O-axis, then the magnitude of the moment of momentum of the bending bar to the O-axis is
An L-shaped

Is o the vertex of a right angle?
To find the moment of momentum (angular momentum), we also need to know the length of the right angle side

The sum of the first n terms of the equal ratio sequence is Sn, A1 is 3 / 2, and S3, S5 and S4 are equal difference sequence, so we can find an

S5-S3=S4-S5
S3+a4+a5-S3=S5-a5-S5
a4+2a5=0
a4+2a4q=0
q=-1/2
an=a1q^(n-1)=3/2×(-1/2)^(n-1)=-3×(-1/2)^n

What is the displacement of a car in the 20s when a car runs at a constant speed of 10m / s for 10s and then at an acceleration of 1.5m/s2 for 10s? What is the average velocity in the whole 20 seconds?

The displacement of the car in uniform linear motion X1 = VT1 = 10 × 10m = 100m, the displacement of the car in uniform acceleration linear motion x2 = vt2 + 12at22 = 10 × 10 + 12 × 1.5 × 100m = 175m, then the displacement in 20s x = X1 + x2 = 275m. The average speed in 20s. V = XT = 27520m / S = 13.75m/s

Xiaohong, Xiaoli and Xiaoqiang each bought some exercise books with the same amount of money. Xiaohong bought 0.6 yuan each, two less than Xiaoqiang,
Xiaoli bought 0.4 yuan each, 3 more than Xiaoqiang. How many exercise books did Xiaoqiang buy? What's the price of each?

If Xiaohong bought x, Xiaoli bought x + 5, then 0.6 * x = 0.4 * (x + 5), then x = 10, then Xiaoli bought 6 yuan in total, and Xiaoqiang bought 12 copies, 0.5 yuan each

The exchange of gases between alveoli and pulmonary capillaries depends on A. respiration B. blood circulation C. respiratory movement D. gas diffusion

Diffusion, choose D
If there is less oxygen in the blood and more oxygen in the alveoli, oxygen will diffuse from the alveoli to the blood. Similarly, carbon dioxide will diffuse from the high concentration of blood to the alveoli