Aunt Wang has 118 pieces of RMB of 2 yuan, 5 yuan and 10 yuan, totaling 500 yuan, of which 5 yuan is equal to 10 yuan Chicken and rabbit in the same cage: Aunt Wang has 118 pieces of RMB of 2 yuan, 5 yuan and 10 yuan, totaling 500 yuan, of which 5 yuan is equal to 10 yuan. How many pieces are there in each of the three kinds of RMB?

The number of sheets of 5 yuan and 10 yuan: (500-118x2) / (3 + 8) = 24 (sheets)
2 yuan: 118-24x2 = 70 (sheet)

Change a 100 yuan note into 5 yuan, 10 yuan and 20 yuan notes, at least one of each kind. How many ways do you have

There are 16 kinds. (the numbers in brackets are used to replace the numbers below) 1. When there are 2 5 yuan, 10 yuan can have (7. 5. 3. 1), 20 yuan can have (1. 2. 3. 4). 10 yuan and 20 yuan are corresponding, that is, when 10 yuan is 7, 20 yuan is 1. The following is the same. 2. When there are 4 5 yuan, 10 yuan can have (6. 4. 2

Math problem wow, fast ~ speed! (give points)
1. A rectangular piece of paper, 96 cm in length and 72 cm in width, is cut into a square of the same size. No surplus is allowed. What is the maximum side length of a square? How many pieces can it be cut into?
2. There are 24 exercise books and 18 pencils, which are awarded to the three good students. Each student is required to get the same amount. How many people can be awarded at most? How many exercise books and pencils can each student get?
3. To tie 96 red flowers and 72 yellow flowers into a bouquet, it is required that the number of red flowers in each bouquet is the same, and the number of yellow flowers is also the same. How many bouquets can be tied at most? How many red flowers and yellow flowers are there in each bouquet?
4. The lengths of the two iron wires are 18 decimeters and 30 decimeters respectively. Now we need to cut them into equal segments, each of which must not have any surplus. What is the maximum length of each segment? How many segments can we cut them into?
5. The floor of Xiaoming's bathroom is a rectangle, 200 cm long and 150 cm wide. If you want to lay floor tiles on the floor of the bathroom, what kind of floor tiles should you choose? Why?
(1) Square brick with side length of 30 cm (2) square brick with side length of 50 cm (3) square brick with side length of 60 cm

2 × 2 × 2 × 3 = 24cm. 3 × 4 = 12 (pieces) answer: the maximum side length of a square is 24cm, and it can be cut into 12 pieces. 2, change the thinking. 2 × 3 = 6 (people) 24 △ 6 = 4 (Books) 18 △ 6 = 3 (pens) answer: you can talk to 6 people, and each person can get 4 exercise books and 3 pens. 3,2 × 2 × 2 × 3 = 24 (bundles) 7

20. (7 points) after learning the knowledge of electric power, Xiao Ming wants to use his home energy meter (as shown in Figure 21) and watch to measure the relevant data of some household appliances

W ice = 3R × 1kwh / 1500r = 1 / 500kwh = 7.2 × 103J (2) the total energy consumption is w = 33r × 1kwh / 1500r = 11 / 50kwh = 7.92 × 104j, and the electric power consumption of electric kettle is w heat = w ice = 7.92 × 104j-7.2 × 103J = 7.2 × 104jt = 1min = 60s

If / x-half / + Y & # 178; - 4Y + 4 = 0, then x * y = / / is an absolute value

|x-1/2|+(y-2)²=0
So X-1 / 2 = 0
y-2=0
So x = 1 / 2, y = 2
So xy = 1

When the mass ratio of metal element to oxygen is 5:2, the molecular weight of a metal oxide with + 2 valence is 0 The symbol of the metal element is ．

In a metal oxide with + 2 valence, if the element symbol of the metal element is m and the oxygen element shows - 2 valence, the chemical formula of the metal oxide is mo; if the relative atomic mass of the metal is x and the mass ratio of the metal element to oxygen is 5:2, then x: 16 = 5:2, x = 40; then the relative molecular mass of the metal oxide is 40 + 16 = 56; if the metal element is calcium, its element symbol is 0 So the answer is: 56; ca

Now there are four rational numbers, - 3,4-6,10, which are used for four operations, so that the result is 24, and each of them must participate in the calculation, and all of them can be used
It's best at 8:00 this evening

((-3×(4-10))--6)((-3×-6)-(4-10))(((-3×-6)-4)+10)((-3×-6)+(10-4))(((-3×-6)+10)-4)(4+(-6÷(-3÷10)))(4+((-6÷-3)×10))(4+(-6×(10÷-3)))(4+((-6×10)÷-3))(4+(10÷(-3÷-6)))(4+((10÷-3)×-6))(((4-10...

If the voltage applied to both ends of the fixed value resistor rises from 6V to 8V, and the current through the resistor changes by 100mA, the electric power of the resistor changes______ ．

When the voltage at both ends of the resistance changes, the resistance remains unchanged. When the voltage at both ends of the resistance is 6V, the current passing through the resistance is I1 = 6vr ①. When the voltage at both ends of the resistance is 8V, the current passing through the resistance is I2 = 8vr ②. The change of current is △ I = i2-i1 = 0.1A ③. The change of electric power of the resistance is △ P = p2-p1 = u22r − u12r ④

It is known that: B & # 178; - n * b = 1. Proof: 1 / B & # 178; + n * 1 / b = 1

B squared - n * b = 1
Divide both sides by B squared
1-N * 1 / b = 1 / b square
So 1 / b square + n * 1 / b = 1

When the power supply voltage is fixed, when the resistance of a certain electrical appliance in the circuit is 60 ohm, it should be given to make 1 / 5 of the total current in the circuit pass through the electrical appliance_ Join one_ If the voltage at both ends of the consumer is 1 / 4 of the total voltage, it needs to be in the circuit_ Join one_ The resistance is less than one ohm

15 Ω in parallel and 180 Ω in series