There are three rooms and double rooms in the room department of a hotel

There are three rooms and double rooms in the room department of a hotel

It was obviously pesticide poisoning. The father immediately picked up the boy from the bed and ran out
Asahi once again penetrated the wind
Ten happy hearts in the evening
The dim light fell again and again
Ah, social harmony and health

(2) There is a tour group of 50 people who stay in a hotel. There are three kinds of rooms in the hotel, including three rooms, two rooms and single rooms. The three rooms are 20 yuan per person per day, the two rooms are 30 yuan per person per day, and the single room is 50 yuan per person per day. If the tour group has a total of 20 rooms, how many rooms are there in each of the three rooms?
There are x people in three rooms, y people in two rooms and Z people in single room,
X+Y+Z=50
X/3+Y/2+Z=20
Finishing x + y + Z = 50
2X+3Y+6Z=120 Y+4Z=20,
Y and Z are integers, so y = 4 and z = 4
X=42
What are the values of X, y and Z?

The value of X is the number of people living in three rooms, 42 people, the value of Y is the number of people living in two rooms, 4 people, the value of Z is the number of people living in single room, 4 people living in three rooms, 42 / 3 = 14 double rooms, 4 / 2 = 2 single rooms, 4 / 1 = 4 rooms, 50 / 3 = 16.2, 16 three rooms plus one double room, the lowest consumption?

A hotel has seven double rooms, three rooms and four rooms. A tour group of 20 people is going to rent these three rooms at the same time. If each room is full
How should we arrange these seven rooms? We must use binary linear equation or ternary linear equation, which must be very detailed

In order to prepare for the new year's Day party, a class wants to buy three kinds of prizes with the price of 2 yuan, 4 yuan and 10 yuan respectively. At least one prize of each kind is bought, and a total of 16 prizes are bought, just with 50 yuan. If a prize of 2 yuan is bought for a piece, (1) use the algebraic formula containing a to express the number of other two kinds of prizes; (2) please design the purchase scheme and explain the reason

(1) Let three kinds of prizes a, B, C, then a ≥ 1, B ≥ 1, C ≥ 1A + B + C = 162a + 4B + 10C = 50, the solution of the equations is: B = 55 − 4A3. C = a − 73. (2) because B ≥ 1, B = 55 − 4A3, so 55-4a ≥ 3, the solution is a ≤ 13, because C ≥ 1, C = a − 73, so A-7 ≥ 3, a ≥ 10, the solution is 10 ≤ a