Please help me answer this, will give brainiest if answerd correct!!

15

Step-by-step explanation:

Total: n counters

Blue counters: 1

Red counters: n - 1

a)

You can take a blue counter first followed by a red counter, or a red counter first followed by a blue counter. We find the probability of each and add them.

Take a blue counter first:

p(blue) = 1/n

Take a red counter second:

p(red) = (n - 1)/(n - 1)

p(blue and red) = 1/n * (n - 1)/(n - 1) = 1/n

or

Take a red counter first:

p(red) = (n - 1)/n

Take a blue counter second:

p(blue) = 1/(n - 1)

p(blue and red) = (n - 1)/n * 1/(n - 1) = 1/n

Add the two probabilities above:

1/n + 1/n = 2/n

The probability you pick a counter of each color is 2/n

b)

We are told the probability of picking one counter of each color is 0.125

2/n = 0.125

2 = 0.125n

n = 2/0.125 = 2/(1/8) = 16

n = 16

red counter: n - 1 = 16 - 1 = 15

last option

step-by-step explanation:

given that δdef is right and isoceles,

assuming that side df is the hypotenuse means that de an ef are the other 2 sides that intersect at 90° and are of equal length.

because they are of equal length, we can say that they are congruent

because they intersect at 90°, their slopes must be opposite reciprocals.

only the last option satisfies these conditions.

you didn't post any answer choices, so its not 100% clear what your teacher is looking for

however, log(15/7) is equivalent to log(15) - log(7)

i'm using the rule log(x/y) = log(x) - log(y)