Junior high school fraction problem. Prawn save There are four questions altogether (1) Given that a + 1 / b = B + 1 / C = C + 1 / A, and a ≠ B ≠ C, can you find the square of a multiplied by the square of B multiplied by the square of C? Please give the reason (2) A ship goes back and forth between port a and port B. from port a to port B, it goes along the water, and from port B to port a, it goes against the current. It is known that the speed of the ship in still water is 8km / h, and the time ratio of sailing against the current is 2:1. One day, it happens to be a rainstorm, and the speed of the current is twice that of the original. This ship goes back and forth for 9h. How far is the distance between port a and port B? (3) In order to speed up the western development, an Autonomous Region decided to build a new highway, which was contracted by Party A and Party B. If Party A works alone, it will be completed on schedule; if Party B works alone, it will take six months to complete. Now Party A and Party B work together for four months, and the rest will be constructed by Party B alone, How long does it take to build this road? (4) The buyer of a shopping mall predicted that a commodity would sell well in the market, so he used 80000 yuan to buy the commodity. After the commodity was put on the market, it was in short supply. The shopping mall used 176000 yuan to buy the second batch of this commodity, which was twice as much as the first batch. However, the unit price of the purchase was 4 yuan more expensive. When the shopping mall sold the commodity, the price was 58 yuan for each piece. Finally, the remaining 150 pieces were sold at a 20% discount and sold out quickly, How much is the total profit of the mall? So many topics Because I know my score is not very much Just ask the prawns to do as much as they can Because it's urgent

Junior high school fraction problem. Prawn save There are four questions altogether (1) Given that a + 1 / b = B + 1 / C = C + 1 / A, and a ≠ B ≠ C, can you find the square of a multiplied by the square of B multiplied by the square of C? Please give the reason (2) A ship goes back and forth between port a and port B. from port a to port B, it goes along the water, and from port B to port a, it goes against the current. It is known that the speed of the ship in still water is 8km / h, and the time ratio of sailing against the current is 2:1. One day, it happens to be a rainstorm, and the speed of the current is twice that of the original. This ship goes back and forth for 9h. How far is the distance between port a and port B? (3) In order to speed up the western development, an Autonomous Region decided to build a new highway, which was contracted by Party A and Party B. If Party A works alone, it will be completed on schedule; if Party B works alone, it will take six months to complete. Now Party A and Party B work together for four months, and the rest will be constructed by Party B alone, How long does it take to build this road? (4) The buyer of a shopping mall predicted that a commodity would sell well in the market, so he used 80000 yuan to buy the commodity. After the commodity was put on the market, it was in short supply. The shopping mall used 176000 yuan to buy the second batch of this commodity, which was twice as much as the first batch. However, the unit price of the purchase was 4 yuan more expensive. When the shopping mall sold the commodity, the price was 58 yuan for each piece. Finally, the remaining 150 pieces were sold at a 20% discount and sold out quickly, How much is the total profit of the mall? So many topics Because I know my score is not very much Just ask the prawns to do as much as they can Because it's urgent

2: Let the flow velocity be a
2*（8-a）=8+a
a=8/3
The current velocity is 16 / 3
The distance between a and B is x meters
x/(16/3+8)+x/(8-16/3)=9
x=20
4. Let the first purchase amount be X,
80000/x=176000/2x-4
x=2000
The first purchase price is 40, and the second purchase price is 44
First profit: (58-40) * 2000 = 36000
Second profit: 3850 * (58-44) = 53900
Third profit: (58 * 0.8-44) * 150 = 360
Total profit: 90260
I'm sorry, I'm also a student of grade two. I can't help so much