3x -3y = 6
or, 3(x -y)= 6
or, x-y =6/3
or, x-y = 2
or, x=2+y........eqn(i)
4x - 7y = 2
substituting the value of x from eqn(i)
or, 4(2+y) -7y = 2
or, 8 + 4y -7y = 2
or, -3y = 2-8
or, y = -6/-3
■ y=2
so in eqn(i)
x= 2+y
x= 2+2
■x = 4
Answer: a) 27.5, b) 5.33.
Step-by-step explanation:
Since we have given that

and n = 180
We need to calculate the sample mean and sample standard deviation.
So, the mean of the distribution of sample means is

The standard deviation of the distribution of sample means is

Hence, a) 27.5, b) 5.33.
Answer: second option Let (2a +1) be an odd number. Let (2b +1) be a different odd number. Because the sum of these two numbers, 2(a + b + 1), is a multiple of 2, it is an even number.
If the numbering of the angles is similar to this:
1 | 2
-----
3 | 4
5 | 6
----
7 | 8
Then none of the the choices are necessarily true.
The equations would have been:
1 = 4 = 5 = 8
2 = 3 = 6 = 7
3 + 5 = 4 + 6 = 180