The time taken by a worker to make a machine part has been reduced from 40 minutes to 24 minutes. How many hours ahead of schedule can a task that used to take 8 hours to complete?

The time taken by a worker to make a machine part has been reduced from 40 minutes to 24 minutes. How many hours ahead of schedule can a task that used to take 8 hours to complete?

If it can be completed x hours in advance, then:
40：（40-24）=8：x
40x=16*8
x=3.2
That is, it can be completed 3.2 hours in advance

18: X = 3:5 out of 10

The solution is 18: x = 3 / 10:5
That is, 3 / 10x = 18 * 5 (inner term product equals outer term product)
That is, 3 / 10x = 90
That is, x = 300

As shown in the figure is a test circuit diagram for a student to measure the resistance and electric power of a small bulb by volt ampere method. It is known that the power supply voltage is 3V and remains unchanged, and the small bulb L is marked with "V"
After closing the switch s, adjust the slide of the sliding rheostat to make the voltage indication number 2.5V, and observe that the current indication number is 0.3A. (1) how many ohm is the resistance of the filament at this time? (2) what is the rated power of the small bulb? (3) how many joules does the sliding rheostat consume when it works for 10s?

（1）R=U/I=2.5/0.3=8.33Ω
（2) P=UI=2.5*0.3=0.75w
(3) When measuring resistance by volt ampere method, the circuit is in series, so the voltage on the sliding transformer is 3-2.5 = 0.5V, and the current through the sliding transformer is 0.3A, so w = uit = 0.5 * 0.3 * 10 = 1.5W

Calculate (3 + 1) (3 ^ 2 + 1) (3 ^ 4 + 1) (3 ^ 8 + 1) (3 ^ 16 + 1) (3 ^ 32 + 1) - 3 ^ 64 / 2
The process should be detailed
Hurry!

Original formula = (3-1) (3 + 1) (3 ^ 2 + 1) (3 ^ 4 + 1) (3 ^ 8 + 1) (3 ^ 16 + 1) (3 ^ 32 + 1) - 3 ^ 64 / 2
=(3^2-1))(3^2+1)(3^4+1)(3^8+1)(3^16+1)(3^32+1)/2-3^64/2
=（3^32-1)(3^32+1)/2-3^64/2
=3^64/2-1/2-3^64/2
=-1/2

If a fixed value resistor is applied with a voltage of 10V at both ends, the current passing through it is 0.4A. If a voltage of 5V is applied at both ends, what is the current passing through the resistor
What are the reasons

If the resistance remains unchanged and the voltage is reduced to half of the original value, the current will also be reduced to half of the original value, 0.2A

The solution set of the following equation x & # 178; - 2x + 1 = 0 is expressed by enumeration

x²-2x+1=0
x1=x2=1
So, the solution set is {1}

Compare the power of (A-4) with that of (A-10) (a + 2)
8 points, can you answer better

(a-4)²-(a-10)(a+2)
=a²-8a+16-a²+8a+20
=36＞0
So (A-4) & #178; > (A-10) (a + 2)

F (x) = what is the function of X & # 178; under the root sign

Exponential function

Xiaoming saw that the power consumption of his refrigerator was 1.2kwh/24h
Xiaoming saw that "power consumption: 1.2kwh/24h" was written on the name plate of his refrigerator____________________________ At the same time, he consulted the manual and knew that the power of the refrigerator was 150W. By timing, he knew that the compressor of the refrigerator worked every day__________ h. (4) if the electricity charge of Xiaoming's city is 0.80 yuan / kWh, the refrigerator alone will pay the electricity charge every month (30 days)_________ So to save electricity as much as possible, please give us a specific measure to save electricity when using the refrigerator_____

24h power consumption 1.2kwh 8 28.8 less open the refrigerator door

Simple calculation of 50 and 1 / 3 times 99 and 1 / 3

50 1 / 3 times 99 1 / 3 = (50 + 1 / 3) * (100-2 / 3)
=50*100-50*2/3+100*1/3-2/9
=5000-2/9
=499 and 7 / 9