Answer:
If Elizabeth randomly chooses her ride in the morning and in the evening, 2/3 is the probability that she'll use a cab exactly one time
Answer: 
Step-by-step explanation:
Given: A bag contains 2 black balls, 4 yellow balls and 4 white balls.
Event A is defined as drawing a white ball on the first draw.
Event B is defined as drawing a black ball on the second draw.
P(B|A) is expressed as the conditional probability of occurring B given that A.
i.e. it is the probability of happening B where A is already happended.
If a white ball is drawn at first, then the number of black ball(4) remains unchanged but the total number of balls (10) will become 9.

Then, 
Question 1:
For this case, the first thing we must do is define variables.
We have then:
x: number of nickels
y: number of dimes
We write the system of equations that adapts to the problem.
We have then:
0.05x + 0.10y = 6.10
x + y = 67
Solving the system we have:
x = 12
y = 55
Answer:
there are 12 nickels
Question 2:
For this case, the first thing we must do is define variables.
We have then:
x: Allan's score
y: Dave's score
We write the system of equations that adapts to the problem.
We have then:
x + y = 375
x = 2y-60
Solving the system we have:
x = 230
y = 145
Answer:
Dave: 145 Allan: 230
Answer:
f(a) = 2a^2 + 4a + 5
Step-by-step explanation:
You just need to replace the "x" with the "a".