From 8:15 to 8:25, the minute hand of the clock turns___ The angle between the hour hand and the minute hand at 2:25 is___ Degree

From 8:15 to 8:25, the minute hand of the clock turns___ The angle between the hour hand and the minute hand at 2:25 is___ Degree

(1) 10 / 60 × 360 = 60 (degrees)
(2) 2 and 25 / 60 × (360 △ 12) = 74 and 1 / 2 (degrees)
25 / 60 × 360 = 150 (degrees)
150-74 1 / 2 = 75 1 / 2 (degree)

The minute hand on the clock turns a minute_____ Degrees, 15 minutes. The needle's turning_____ Degree

360 degrees in 3600 seconds
1 minute = 60 seconds, 6 degrees
15 minutes 90 degrees

Solving mathematical problems of equation
① 0.3（y-2)=1-(x+1)/5
②(0.04x+0.09)/0.2-(0.1y-0.3)/0.4=1.5
Er. It's a system of linear equations with two variables. If you don't play well, you can make do with it

1、0.3（y-2)=1-(x+1)÷5
0.3y-0.6=1-x÷5+0.2
0.3y=1+0.6-x÷5+0.2
0.3y=1.6+0.2-x÷5
0.3y=1.8-x÷5
y=1.8-x÷5÷0.3
y=1.8-x÷1.5
y-1.8=－x÷1.5
y+x=1.8÷1.5
y=2
x=4

The price of a color TV set is reduced by 3 / 8, which regards () as unit "1"

The original price, the present price is 5 / 8 of the original price==

Let the function f (x) defined on the natural number set n satisfy f (n) = {n + 13, (n ≤ 2000); f [f (n-180)] (n > 20000, try to find the value of F (2011)

f(2011)=f[f(2011-180)]=f[f(1831)]=f(1831+13)=f(1844)=1857

Mathematical inequality system in the second semester of junior one
X－2÷3－〔2X－1〕＜1

Original formula = x-2x + 1 ＜ 1 + 2 / 3
-X+1＜5/3
-X＜5/3-1
-X＜2/3
X＞2/3

What does 12 * 0.5 mean

12*0.5=12×0.5=6
It is also possible to define a new operation and do it according to the requirements of his topic

When the earth revolves around the sun, the distance it passes in one second is the fourth power of 3 * 10. The earth's revolution speed is? (meters per second) or? (kilometers per hour)

The earth's revolution speed is the highest at perihelion, 30.3 km / s, and the lowest at aphelion, 29.78 km / s, with an average speed of 29.79 km / s

How to do questions 9 and 10 on page 71 of the eighth grade volume of mathematics of people's education press

9.82mm
10. If the water depth is x feet, the reed length is (x + 1) feet
x²+(10/2)²=(x+1)²
The solution is x = 12  x + 1 = 13 (feet)
A: the depth of water is 12 feet and the length of reed is 13 feet

(1) What is the relationship between the coordinates of two points with respect to X-axis symmetry? (2) what is the relationship between the coordinates of two points with respect to Y-axis symmetry? (3) about the origin
(3) What's the relationship between the coordinates of two symmetrical points at the origin

(1) The sum of the two ordinates of x-axis symmetry is equal to zero, and the abscissa is the same
(2) Y axis is the sum of abscissa is zero, the ordinate is the same
(3) About the origin symmetry, that is, the sum of abscissa is zero, and the sum of ordinate is also zero