If the ratio of girls in a class to the whole class is 7:10, how many percent more girls than boys? Formula

If the ratio of girls in a class to the whole class is 7:10, how many percent more girls than boys? Formula

Boys: 1-7 / 10 = 3 / 10
（7/10-3/10）/（3/10）=133%

Girls account for 2 / 5 of the class, and boys are several percent more than girls

(1-2/5-2/5)×100%=20%

9dm2 power = () m2 power 79cm = () m 35g = () kg 56ml = () l 5kg = () t 123dm3 power = () m3 power

9dm²=0.0009m² 79cm=（0.79 ）m 35g=（0.035 ）kg 56ml=（0.056 ）L
5kg=（0.005 ）t 123dm³=( 0.123)m³

The starting price of a taxi in Yancheng is 5 yuan and 3 kilometers, and then 1.8 yuan per kilometer. Xiaofang pays 12.2 yuan from school to grandma's house. How many kilometers is it from school to grandma's house?
A cuboid container, measuring from the inside, is 10 cm long and 8 cm wide. The water depth in the container is 4.5 cm. Now immerse a stone in the water, and the water surface rises to 6 cm. What is the volume of this stone?

Suppose the distance from school to grandma's home is x km, 5 + (x-3) * 1.8 = 12.2, and the solution is x = 710 * 8 * (6-4.5) = 120 (cubic centimeter)

If the length of a rectangle is reduced by 5cm, the area will be reduced by 20cm. If the width is increased by 3cm, the area will be increased by 30cm. What is the area of the original rectangle

20 ／ 5 × (30 ／ 3) = 40 square centimeter, please click adopt as the answer

If the perimeter of triangle ABC is 20, the area is 10 times of root 3, and a = 60 degrees, what is BC?

Let AB = C, BC = a, AC = B of △ ABC
a+b+c=20……………………………………………………… （1）
S△ABC=(1/2)bcsinA=(1/2)BC*(√3/2)=(√3/4)BC=10√3
So: BC = 40 （2）
According to the cosine theorem:
a^2=b^2+c^2-2bccosA=b^2+c^2-2bc(1/2)=b^2+c^2-bc…… （3）
LIANLI (1) (2) (3) obtained:
a^2=[20-(b+c)]^2=b^2+c^2-40
===> 400-40(b+c)+(b+c)^2=b^2+c^2-40
===> 440-40(b+c)+b^2+2bc+c^2=b^2+c^2
===> 40(b+c)=440+2bc=440+80
===> 40(b+c)=520
===> b+c=13
So, a = 20 - (B + C) = 7

The results are as follows: 1. A 50kg sled is loaded with 350kg goods. A horse pulls the sled along the horizontal road to transport the goods to the freight yard 3000m away at a uniform speed. After 2.1 × 106j work is done, how much friction does the sled suffer in the process of moving
2.1 × 106j / 3000m = 700n

Yes, because in the horizontal road, in the direction of gravity does not pass a distance, so only to overcome friction work
But there is something wrong with your calculation: w = FS = 2.1 × 10 ^ 6 × 3000 = 6.3 × 10 ^ 9N
Note: in the middle school entrance examination, the unit can not be written, as long as the final result is written
Hope to help you

Two 40cm long iron wires, one is surrounded by a square, the other is surrounded by a 15cm long rectangle, the area of the rectangle is several percent of the square area
shi 15cma!

Side length of square = 40 / 4 = 10 (CM)
Width of rectangle = 40 / 2-15 = 20-15 = 5 (CM)
Square area = 10x10 = 100 (square centimeter)
Area of rectangle = 15x5 = 75 (square centimeter)
The area of a rectangle is equal to that of a square
75/100
=75%

If 2n + 1 power of 2 + 4 power of n = 48, find the value of n,

2n + 1 power of 2 + n power of 4 = 48
2n power of 2 × 2 + 2n power of 2 = 4 power of 3 × 2
2n power of 2 × (2 + 1) = 4 power of 3 × 2
2n power of 2 = 4 power of 2
2n=4
n=2

Ten practical problems of profit and loss

1. If students go boating, if each boat takes 4 people, then 3 boats are less; if each boat takes 6 people, then 2 boats are less, ask students how many people are there in total? How many boats have they rented? If each boat takes 4 people, then 12 people are more, if each boat takes 6 people, then 2 boats are less. Number of boats: (12 + 2) / (6-4) = 7 boats, number of people: 4 * 10 = 40 people