Given are three married couples.
So, let us assume there are 3 men and 3 women
They are sitting in a row of 6 empty seats
There is a definite order constraint that each woman will sit left to her husband. The first woman gets 3 options to choose from 3 available seats. The second woman has two options left as already one seat is filled by the first woman. The last woman has one option left. So, it is 
So, number of ways is 3! =
= 6 ways.

3*boys=2*18
3*boys=36
boys=12
12+18=30
total number of students: 30
Answer:
Step-by-step explanation:
2
x
2
+
8
−
4
x
+
3
x
−
6
x
2
+
7
Subtract
6
x
2
from
2
x
2
.
−
4
x
2
+
8
−
4
x
+
3
x
+
7
Add
8
and
7
.
−
4
x
2
−
4
x
+
3
x
+
15
Add
−
4
x
and
3
x
.
−
4
x
2
−
x
+
15
Answer:
Step-by-step explanation:
The absolute value of z is the distance between the point graphed from the complex number and the origin on a complex plane. In a complex plane, the x axis is replaced by R, real numbers, and the y axis is replaced by i, the complex part of the complex number. Our real number is positive 3 and the complex number is -5, so we go to the right 3 and then down 5 and make a point. Connect that point to the origin and then connect the point to the x axis at 3 to construct a right triangle that has a base of 3 and a length of -5. To find the distance of the point to the origin is to find the length of the hypotenuse of that right triangle using Pythagorean's Theorem. Therefore:
and
and
