Answer:
5/8
Step-by-step explanation:
The number of possible outcomes after flipping 3 coins is $2 \times 2 \times 2 = 8$. If the dime isn't heads, we need both the penny and nickel to be heads. If the dime is heads, the other two could be anything. So there are a total of $1+(2 \times 2)=5$ ways for us to get at least 6 cents. The answer is $\boxed{\dfrac58}.$
Answer:
A triangle with side lengths 4 cm, 5 cm, and 15 cm
Step-by-step explanation:
In order to form a triangle with given side lengths, sum of any two sides must always be greater than the third side.

I think the answer is 22.5
Answer:

Step-by-step explanation:
a=3, b=-15, c=20
Discriminant can be calculated as


The roots are imaginary
The solution is


The roots are not real i.e these are imaginary
a=3, b=5, c=-8
Discriminant can be calculated as


The roots are real
By quadratic formula method
The solution is



which are required roots.
I choose this method because I can get the solutions directly by substituting the values in formula, and I don't have to guess the possible solutions.