Math problem (to be solved in elementary school) (it's better not to use equation, but it doesn't matter) In a certain math exam, 52 students in the class took part in five questions, and they just did 181 right questions. It is known that each student does at least one right question, seven people do one right question, six people do all five right questions, and the number of people do two and three right questions is the same, so how many people do four right questions? If a and B are two natural numbers, and a / 5 + B / 11 = 37 / 55, what is the value of a + B?

Math problem (to be solved in elementary school) (it's better not to use equation, but it doesn't matter) In a certain math exam, 52 students in the class took part in five questions, and they just did 181 right questions. It is known that each student does at least one right question, seven people do one right question, six people do all five right questions, and the number of people do two and three right questions is the same, so how many people do four right questions? If a and B are two natural numbers, and a / 5 + B / 11 = 37 / 55, what is the value of a + B?

Let X be the number of people in the right four lanes,
4x+1*7+5*6+(52-x-7-6)/2*(2+3)=181
x=31
2、A/5+B/11=(11A+5B)/55=37/55
That is 11a + 5B = 37, a and B are two natural numbers, so a = 2 and B = 3
A+B=5

Several mathematical problems, only equations!
1. A project is completed by team a and team B. It takes 24 days for team a to complete it alone and 16 days for team B to complete it alone. Team a will do it for 5 days first, and then the two teams will cooperate. How many more days can we complete 5 / 8 of the whole project?
2. The retail price of a certain commodity is 600 yuan per piece. In order to adapt to the market competition, the price of the commodity is reduced by 20% of the retail price, and the profit is still 15%. How much is the purchase price per piece?
Please list the equation!
thank you

1. It will take X more days
5/24+X(1/16+1/24)=5/8
2. Set the purchase price as: X Yuan
600×80%-20=（1+15%）x

Party A and Party B moved a batch of goods together. Party A moved half of the goods in four minutes. After Party A took an hour's rest, Party A and Party B moved the goods together for three minutes. After moving the goods, the same batch of goods came the next day. Just like Party B, how much does he need to move?

In this topic, "a takes an hour off" is actually nonsense
The efficiency of a is 0.5 / 4 = 0.125, that is, 1 / 8 per minute. According to the meaning of the question, the efficiency of B should be (1 / 2 - 1 / 8 * 3) / 3 = 1 / 24,
Kedeb can only move 1 / 24 of the goods per minute, and it takes 24 minutes to complete the task alone
I don't know what you think of the one on the first floor, and the title is wrong. Logically, a moves half of it in four minutes, and B moves it alone in eight hours. Logically, it doesn't make sense, does it?

Pay attention to write the quantity relation
A bag and B bag of flour, a bag 56 kg, B bag 34 kg, two bags to eat the same amount of flour, a bag is twice the weight of B bag, a bag and B bag to eat how many kg of flour?

The flour in bag a is 56-34 kg more than that in bag B = 22 kg
After eating the same flour, a is 22 kg more than B,
At this time, a is twice the weight,
Then there are 22 kilograms left in B and 44 kilograms left in a
Then the amount of flour eaten by Party A and Party B = 56-44 = 12kg