X=number of boys
y=number of girls.
We can suggest the following system of equations:
x+y=33
x/y=3/8
We solve this system of equations by substitution method.
x/y=3/8 ⇒x=3y/8
(3y/8)+y=33
least common multiple=8
3y+8y=33*8
11y=33*8
y=(33*8)/11
y=3*8
y=24
x+y=33
x+24=33
x=33-24
x=9
number of boys /total number of students=9/33=3/11
There are 9 boys and 24 girls in the class.
Answer: C: 9. since 3/11 of the students are boys.
Answer: x = 3
Explanation:
If the two triangle are congruent then all of their sides are also congruent.
4x + 1 = 13
4x = 13 - 1
4x = 12
x = 12/4 = 3
Answer:
Perimeter = 42 cm
Step-by-step explanation:
XY = 8 cm because ΔWXZ ≅ ΔYZX
Perimeter = 8 + 14 + 20 = 42 cm
In this question , it is given that, Perimeter of a rectangular room is 270 yards. Longer side of the room is 15 yards longer than the shorter side.
So if we let shorter side be x, then longer side is

And perimeter is equal to sum of all sides, that is

So the smaller side is 60 yards , and longer side is 15 more then 60 that is 75 yards .
Answer:
There is enough evidence to support the claim that the percent that the goalkeeper guessed correctly is less than 50%.
Step-by-step explanation:
We have to perform an hypothesis test on a proportion.
We have a sample of size n=138, a sample mean of p=0.41.
The standard error is SE=0.043.
We want to test the claim that the real proportion is below 50%.
Then, the null and alternative hypothesis are:

The significance level is α=0.05.
The z-statistic can be calculated as:

The P-value (left tail test) for this z-statistic is:

The P-value is smaller than the level of significance, so the effect is significant. The null hypothesis is rejected.
There is enough evidence to support the claim that the percent that the goalkeeper guessed correctly is less than 50%.