Master Wang planned to process 120 parts today. In fact, he processed 7 / 12 of all the parts in the morning, 38 in the afternoon and 42 in the evening. That's a big deal How much of the task did Master Wang overfulfill on that day?

A total of 70 + 38 + 42 = 150 pieces were processed
Over 30
30 / 120 = quarter

Master Wang planned to process 120 parts. In fact, he processed 7 / 12 of all the parts in the morning, 38 in the afternoon and 42 in the evening. Master Wang overfulfilled a few percent of the task that day

(120×7/12＋38+42-120)÷120＝1/4

Master Li planned to make 120 parts today. In fact, he finished 12 / 7 of the plan in the morning, processed 38 parts in the afternoon, and processed 42 parts in the evening?
How much of Master Li's plan has been overfulfilled on this day?

2/7+38÷120+42÷120=20/21
20 / 21 of the plan has been completed

Master Wang has to process 120 parts, but there are more than the original plan. In the morning, he processed all 7 / 12 parts, in the afternoon, he processed 38 parts, and in the noon, he processed 42 parts. How many more parts?

Design experiments to prove that alcohol combustion produces water and carbon dioxide, phenomenon and conclusion

Light the alcohol lamp and cover a beaker above. You can see that there are water droplets on the wall of the beaker. Then put clear lime water into the beaker. If there is turbidity, it means there is carbon dioxide

How to design experiments to test the composition of alcohol

After the alcohol is ignited, a cold and dry beaker is used to cover the flame. There are water droplets on the inner wall of the beaker, which proves that the composition of the alcohol has hydrogen. When a beaker stained with clear lime water is used to cover the flame, turbidity appears, which proves that the composition of the alcohol has carbon

How to design an experiment to verify the incomplete combustion of alcohol or gasoline to produce carbon monoxide?

When the generated gas is introduced into the palladium chloride solution, if there is black solid palladium precipitation, it indicates that there is Co

How to design experiments to prove the composition of wood
There should be two experimental steps, two experimental phenomena and two conclusions. I hope I can help you to answer them one day

I don't know if I can do this
1. Add concentrated sulfuric acid to the sawdust; the sawdust turns black; the main component is carbon
2. Light a small amount of sawdust (wood block) and cover it with a drying beaker; there are small drops of water or mist; there are h elements. (o can't prove)
Think again,

When heating a substance, which part of the flame of the alcohol lamp should the heated substance be placed in? Can you design an experiment to prove the scientific truth of this practice?

Outer flame
Take a match
Put it across the fire
Take out
Look at the charred section
Found a match in the outer flame
Black first
This proves that the temperature of the outer flame is the highest
So it's heated with an external flame

Design a simple experimental program to verify that the components of the chromosome are DNA and protein
(1) Experimental principle: protein reacts purple with biuret reagent; DNA reacts blue with diphenylamine reagent in hot water bath
(2) Materials and tools: chromosome extract, diluted egg white solution, DNA extract, etc. (other materials and tools are optional)
(3) The experimental steps were as follows
1. Take 4 clean test tubes, numbered 1, 2, 3 and 4 respectively
2. Take No.1 and No.2 test tubes and add the same amount of chromosome extract and respectively; take No.3 and No.4 test tubes and add the same amount of chromosome extract and respectively
3. Add equal amount of in tubes 1 and 2, and add equal amount of in tubes 3 and 4, and heat them in hot water
4. The color changes of No.1 and No.2, No.3 and No.4 tubes were observed
(4) Results: No.1 and No.2 test tubes proved to contain chromosome; No.3 and No.4 test tubes proved to contain chromosome
Variant exploration: please design experiments according to the above principles to explore whether the components of chromosome contain protein
1. Hypothesis: the components of chromosome contain protein
2. Experimental steps
Step 1: take two clean test tubes, numbered 1 and 2 respectively
Step 2:
Step 3:
Step 4:
3. Results and conclusion
If, but not in tube 2, it means that the hypothesis is correct. If, in two tubes, it means that the hypothesis is wrong

2. Diluted egg white aqueous solution chromosome extract DNA extract
3. Biuret reagent diphenylamine reagent
(4) The protein turns blue and the chromosome contains DNA
In the second step, chromosome extract was added to tube 1, and the same amount of DNA solution was added to tube 2
The third step is to add the same amount of biuret reagent to the two test tubes and take a water bath
The fourth step is to compare the color changes of the two tubes
3. If tube 1 appears purple, it will appear purple

Master Wang planned to process 120 parts today. In fact, he processed 7 / 12 of all the parts in the morning, 38 in the afternoon and 42 in the evening. That's a big deal How much of the task did Master Wang overfulfill on that day?