Answer:
11
Step-by-step explanation:
Answer: Second option.
Step-by-step explanation:
Let be "e" the number of easy puzzles Tina solved and "h" the number of hard puzzles Tina solved.
Set up a system of equations:

You can use the Eliminationn Method to solve this system of equations:
- Multiply the first equation by -30.
- Add the equations.
- Solve for "h".
Therefore, through this proccedure, you get:

3∅ can be rewritten as (2∅+∅)
sin(3∅) = sin(2∅ + ∅<span>)
Opening brackets on the right hand side;
= sin2</span>∅ cos ∅ + cos2∅sin<span>∅
</span><span>This simplifies to;
= 2sin</span>∅cos^2∅ + sin∅ (1- 2sin^2∅<span>)
= sin</span>∅ (2cos^2∅ + 1 - 2sin^2∅<span>)
= sin</span>∅ (2(1 - sin^2∅) +1-2sin^2∅<span>)
= 3sin</span>∅ - 4sin^3<span>∅</span>