Solution: A/B=C,1/b = a/c; B/A= 1/C， 1/A= 1/BC

Therefore,1/b = a/c1/a =1/BC.

Therefore, after sharing,1/a =1/BC1/b = ab/BC.

2. The product of three different prime numbers is 385. What is the sum of these three prime numbers?

Solution: 385 = 5 * 7 * 1 1

5+7+ 1 1=23

3. In the figure below, AB=AC=BC, AM=MN=NB, AE=EF=FC, and the shaded part in the figure accounts for the whole triangle area (expressed by fraction) ().

A

Medical engineering

N F

Shaded part c

The answer is 4/9.

4: There are three prime numbers whose vicious product is 100 1. What are these three numbers?

Solution: solution: 100 1 decomposition prime factor:1001= 7 *1*13.

So these three numbers are 7, 1 1, 13.

5. A rectangular ventilation duct, 4 meters long, 10 decimeter wide and 0.8 decimeter high. How many square meters of iron sheet is needed to make the ventilation duct with 10 section? The answer is 86.4 square meters. How to calculate?

Solution: The ventilation pipe does not have two opposite bottom surfaces, and one required iron sheet is its side surface area, that is, (40* 10+40*0.8)*2=864 square decimeter,164 */kloc-0 = 8640 square decimeter if it is wrong.

If it is not enough, there are: /question/65308 148.html? si= 10

Note: Reference Baidu knows other people's problems.