The number of male students is four fifths of that of female students. What is the proportion of female students in the class? I'm in a hurry

The number of male students is four fifths of that of female students. What is the proportion of female students in the class? I'm in a hurry

Use the special value method. The classical thinking method of solving multiple choice questions, find the right answer instantly
If the number of girls is 5 and the number of boys is 4, then the number of students in the class is 9 and girls account for 5 / 9
x+4/5x=1 x=5/9
Set the female as X, the male as 4 / 5x, the total number is 1
4/5X+X=1
X=5/9
5 / 9 divided by 1 = 5 / 9
If the number of female students is x, the number of male students is 4 / 5x, and the total number is 1
4/5X+X=1
X=5/9
5 / 9 divided by 1 = 5 / 9, so girls account for 5 / 9
Because boys are four fifths of girls, men are four fifths of women, and girls are five fifths of women
Set the number of girls as X. 4 / 5x + x = 1 9 / 5x = 1 x = 5 / 9 female students account for 5 / 9 of the class. Oh, I will add the next step 4 / 5x + x = 1 4 / 5x + 5 / 5x = 1 9 / 5x = 1 x = 9 / 5
What is the value of sin53 ° cos23 ° - sin23 ° cos53
sin53°cos23°-sin23°cos53°
=sin(53°-23°)
=sin30°
=1/2
The number of boys in class 51 accounts for four fifths of the number of girls, and how many of the number of girls in the class?
There are x boys in the class and y girls in the class
Four fifths x = y
{
X+Y=1
X + four fifths x = 1
Nine fifths x = 1
X = five ninths
Y = four ninths
X is male, accounting for the whole class
Y is female, accounting for the whole class
Sin23 ° cos68 ° - cos23 ° sin68 ° values
sin23°cos68°-cos23°sin68°
=Sin (23-68 degrees)
=Sin (- 45 degrees)
=-Root 2 / 2
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The number of boys in class five (1) is equivalent to four fifths of the number of girls, and the number of boys is equivalent to what percentage of the number of the whole class?
Suppose there are x boys and y girls, then x = 4 / 5 * y, so x / (x + y) = 4 / 5 * y / (4 / 5 * y + y) = 4 / 9 for boys
Sin130 degrees (1 + root 3tan10 degrees) =?
It's equal to one
It's exactly equal to one
Do not believe you use calculator to calculate!
There are 24 boys and 20 girls in a class. How many times is the number of boys? What is the proportion of girls to boys?
A: boys are 1.2 times as many as girls, girls are 56.2 times as many as boys
[2sin130 + sin100 (1 + radical 3tan370)]
The numbers of 130 represent degrees. There is no place to divide by the root sign (1 + cos10), so it is written here. Do not look up the table to evaluate
Calculation molecule = [2sin50 + cos10 (1 + radical 3tan10)] = 2sin50 + cos10 +. 5 radical 3sian10 = 2sin50 + 2 (. 5cos10 +. 5 radical 3sian10) = 2sin50 + 2 (cos60cos10 + sin60sian10) = 2sin50 + 2cos50 = 2 radical 2sian95 = 2 radical 2cos5 denominator = radical 2cos5 result = 2
The number of male students in class 51 is seven eighths of that of female students. What is the proportion of male and female students in the class?
Boys account for seven out of fifteen and girls for eight out of fifteen
8 + 7 = 15, 7 / 15, 8 / 15
Sin130 (1 + radical 3 / tan80)
calculation
The original formula is sin 50 ° (1 + √ 3 cot 80 °) = sin 50 ° (1 + √ 3 Tan 10 °) = sin 50 ° (1 + √ 3 sin 10 ° / cos 10 °) = sin 50 ° (COS 10 ° + √ 3 sin 10 °) / cos 10 °. Because cos 10 ° + √ 3 sin 10 ° = 2 [(1 / 2) cos 10 ° + (√ 3 / 2) Si
=-Sin50 (1 + √ (3ctg10)) with a calculator, just press. Questioning: the process of thinking