Equation 60% x + 48 = 75% X

60%x+48=75%x
0.6x+48=0.75x
0.15x=48
x=320

The solution ratio is 0.75: x = 1.25:2
Additive writing

x = 1.2

The proportion of solution is 25 parts x = 75 parts 1.2

75X=30
X = two fifths

Cylinder surface area, volume formula, cone volume formula!

S-column = 2 π R & # 178; + CH
V-pillar = sh
V-cone = 1 / 3SH

The perimeter of a rectangular grassland is 90m, and its width is half of its length. How many square meters is the area of this grassland?

90 / 2 = 45m, this is the length + width
So we can calculate length = 30m, width = 15m
S = length * width
S = 30 * 15 = 450 square meters

Use the rounding method to approximate the following numbers as required
12.17, 860400 (3 significant digits reserved)

12.2
8.60*10^5

A tunnel is 760 meters long. How long does it take for a 240 meter long train to pass through the tunnel at a speed of 25 meters per second?

The distance through the tunnel is the length of the car plus the length of the tunnel
That is to say, the front of the car enters the tunnel until the rear of the car leaves the tunnel
So if the speed is 25, the time is (760 + 240) / 25 = 40 seconds

As shown in the figure, the quadrilateral ABCD is inscribed on the circle O, BD is the diameter of the circle O, AE is vertical to CD, the perpendicular foot is e, Da bisector angle BDE. 1
2. If the angle DBC = 30 degrees and de = 1cm, find the length of BD
Please attach your drawing. Let me see if it's the same

1. It is proved that connecting OA ∵ AE ⊥ CD ∵ DAE ∵ EDA = 90 ∵ Da bisection ∵ BDE ∵ BDA = EDA ∵ OA = OD ∵ oad = BDA ∵ oad = EDA ∵ OAD ∵ DAE = 90 ∵ OAE = 90 ∵ AE is the tangent line of circle O ∵ DCB = 30 ∵ BDC = 90 ∵ DCB = 60 ∵ BDE = 180 ∵ BDC = 18

Is the speed of the signal equal to the speed of light?
Such as the title

To be exact, the speed of the photoelectric magnetic signal is equal to the speed of light

There are two billing methods for mobile phones. 1. Pay 22 yuan monthly rent, and then charge 0.2 yuan per minute. 2. No monthly rent, call fee is 0.4 yuan per minute. When the number of minutes of each month's talk time is the same, the two billing methods get the same fee. Under what circumstances is a more cost-effective method for each month's talk time

When the monthly call time is a minute, the cost of the two billing methods is the same
22+0.2a=0.4a
The solution is a = 110
When a > 110, a way is more economical

Equation 60% x + 48 = 75% X