3. After the heavy snow, Xiao Ming and his father walk together to measure the perimeter of a circular garden. Their starting point and direction are exactly the same. Xiao Ming's average step length is 54 cm, and his father's average step length is 72 cm. Because their footprints overlap, and they all return to the starting point after a walk, only 60 footprints are left on the snow. How many square meters is the area of the garden? 4. The charges of tap water in a city are as follows: 1.8 yuan per ton for each household less than 4 tons of water, 3 yuan per ton for each household more than 4 tons of water, 26.4 yuan for each household a and B in a month, and the water consumption ratio is 5:3. How many yuan for each household a and B? 5. When parents and grandmothers travel by air, the quality of their luggage exceeds that of the free luggage. They have to pay extra. They pay 4 yuan in total, and their luggage weighs 150 kg in total. If one person is allowed to take the luggage, they will pay 8 yuan in addition to the free part?

3. After the heavy snow, Xiao Ming and his father walk together to measure the perimeter of a circular garden. Their starting point and direction are exactly the same. Xiao Ming's average step length is 54 cm, and his father's average step length is 72 cm. Because their footprints overlap, and they all return to the starting point after a walk, only 60 footprints are left on the snow. How many square meters is the area of the garden? 4. The charges of tap water in a city are as follows: 1.8 yuan per ton for each household less than 4 tons of water, 3 yuan per ton for each household more than 4 tons of water, 26.4 yuan for each household a and B in a month, and the water consumption ratio is 5:3. How many yuan for each household a and B? 5. When parents and grandmothers travel by air, the quality of their luggage exceeds that of the free luggage. They have to pay extra. They pay 4 yuan in total, and their luggage weighs 150 kg in total. If one person is allowed to take the luggage, they will pay 8 yuan in addition to the free part?

3. 72-54 = 18, 54 / 18 = 3, that is, when Dad took the third step, it coincided with Xiaoming's fourth step. At this time, the father and son left a total of 3 + 3 = 6 footprints, and then went on, it was the same cycle. 60 / 6 = 10, that is, there were six such cycles. Calculate the length of each cycle: 72 * 3 + 54 * 4, multiply by 6, that is the perimeter of the garden, the perimeter divided by 3.14 is the diameter, half of the diameter is the radius, The square of the radius times 3.14 is the area
4. When Party B uses 4 tons of water and Party A uses 4 * 5 / 3 tons of water, Party B should pay 4 * 1.8 = 7.2, and Party A should pay 4 * 1.8 + (4 * 5 / 3-4) * 3 = 7.2 + 8 / 3. At this time, Party A and Party B pay 14.4 + 8 / 3 in total. Since then, the water fees paid by Party A and Party B are the same price, that is, 3 yuan per ton, according to their water use ratio of 5:3, After that, the ratio of water charges they paid was 5:3. And 26.4-14.4-8 / 3 = 28 / 3 was the total amount of water charges they paid. Combined with the ratio of 5:3, it can be calculated that the water charge paid by Party B was 28 / 3 * 3 / (5 + 3) = 3.5, then the total water charge paid by Party B was 3.5 + 7.2 = 10.7 yuan, and the total water charge paid by Party A was 26.4-10.7 = 15.7 yuan
5. The increased fee: 8-4 = 4 yuan, which is due to the charging of two people's free luggage weight as overweight. If the charging of each person's free gift weight is overweight, it should be 4 / 2 = 2 yuan, that is to say, if 150 kg is charged as overweight, the payable fee: 2 * 3 + 4 = 10 yuan, that is, 10 / 150 = 1 / 15 yuan per kg, It can be calculated that the actual overweight weight of three people is: 4 / (1 / 15) = 60kg, then the free weight of three people is: (150-60) / 3 = 30kg

A math problem of grade 4 in primary school
A basket of apples weighs 565kg together with the basket. Divide the apples into three parts and put them in the original basket three times. The first time they weigh 195kg, the second time they weigh 245kg and the third time they weigh 175KG. How many kg do the basket and the apples weigh?

1970922GHJ ,
Basket weight:
(195 + 245 + 175-565) / (3-1) = 25 (kg)
Apple weight:
565-25 = 540 (kg)

1. The surface area of a cylinder is 628 square centimeters. The radius of the bottom of the cylinder is one third of its height. What is the side area of the cylinder
2. The volume of a cylinder is 250 cubic centimeter and the side area is 100 square centimeter
3. The radius ratio of cone to cone is 1:3, the height ratio is 8:9, and what is the volume ratio
4. The bottom area of a cylindrical tank is 12.5 square decimeters, containing 12 cm high water. Put a piece of iron into the water, and the water surface rises to 15 cm. Calculate the volume of the iron

1. If the radius is r, the height is 3R
2*3.14*r^2+2*3.14*r*（3r)=628
6.28r^2+18.84r^2=628
25.12r^2=628
r^2=25
r=5
Height 3R = 3 * 5 = 15 (CM)
The side area of this cylinder is: 2 * 3.14 * 5 * 15 = 471 (cm ^ 2)
2.2 ∏rh=100
∏rh=50
Π R ^ 2H = 250
(∏rh)r=250
50r=250
r=5
3 r1/r2=1/3 h1/h2=8/9
v1:v2=(1/3∏r1^2h1):(1/3∏r2^2h2)
=(r1/r2)^2*(h1/h2)
=1/3*1/3*8/9
=8/81
=8:81
4 1250*(15-12)
=1250*3
=3750(cm^3)