Set x as adult tickets.
Set y as children's tickets.
x + y = 15
30x + 20y = 270
Solve for x in the first equation.
x + y = 15
x = 15 - y
Plug this into the second equation.
30x + 20y = 270
30(15 - y) + 20y = 270
450 - 30y + 20y = 270
450 - 10y = 270
-10y = -180
y = 18
If there is 18 childrens tickets, there should be -3 adult tickets.
This is impossible, and this impossible answer occured because the question is written wrong.
There are a total of 15 tickets
The smallest costing ticket is the childrens ticket, which costs 20$.
If he only bought children tickets, this would be 20x15 which is 300$.
300$ is over 270$, which makes the question impossible.
Answer: x=12
Step-by-step explanation:

The sum of the angles of the triangle is 180°:

Divide both parts of the equation by 4:

A) the null hypothesis is incorrectly accepted when it is false
Answer:
x = 2, y = 1
Step-by-step explanation:
- 7x + 5y = 19
- -7x - 2y = -16
Use the elimination method to solve the system of equations. Add the terms from top to bottom. 7x and -7x cancel out.
0 + 3y = 3
Divide both sides by 3.
y = 1
Substitute 1 for y into the first equation.
7x + 5(1) = 19
7x + 5 = 19
Subtract 5 from both sides.
7x = 14
Divide both sides by 7.
x = 2
Its 11/12 , you need to divide the "wanted results" (every dog which is either black, with spots or both ) by every every possible result ( all dogs ). so 11/12=0.92