Answer:
a) 
b) 
Step-by-step explanation:
From the question we are told that:
3 coin are tossed
Therefore
Sample space 
Generally the sets that correspond with the result of at most one tail is therefore given as follows

Therefore
The result is at most one tail when

Answer:
(2, 4)
General Formulas and Concepts:
<u>Pre-Algebra</u>
Order of Operations: BPEMDAS
- Brackets
- Parenthesis
- Exponents
- Multiplication
- Division
- Addition
- Subtraction
Equality Properties
- Multiplication Property of Equality
- Division Property of Equality
- Addition Property of Equality
- Subtract Property of Equality
<u>Algebra I</u>
- Solving systems of equations using substitution/elimination
Step-by-step explanation:
<u>Step 1: Define Systems</u>
y = 2x
x = -y + 6
<u>Step 2: Solve for </u><em><u>y</u></em>
<em>Substitution</em>
- Substitute in <em>x</em>: y = 2(-y + 6)
- Distribute 2: y = -2y + 12
- Isolate <em>y</em> terms: 3y = 12
- Isolate <em>y</em>: y = 4
<u>Step 3: Solve for </u><em><u>x</u></em>
- Define equation: x = -y + 6
- Substitute in <em>y</em>: x = -4 + 6
- Add: x = 2
(3/5)(2/5)=6/25
.............................
11 ÷ 2 = 5.5
Ethan ran 5.5 miles per hour