An amusement park reports that the probability of a visitor riding its largest roller coaster is 30 percent, the probability of a visitor riding its smallest roller coaster is 20 percent, and the probability of a visitor riding both roller coasters is 15 percent.
which equation can be used to calculate the probability of a visitor riding the largest or the smallest roller coaster?

The equation is P(L or S) = 0.3 + 0.2 - 0.15

Step-by-step explanation:

* Lets study the meaning of "or" , "and" on probability

- The use of the word "or" means that you are calculating the

  probability  that either event A or event B happened

- Both events do not have to happen

- The use the word "and" means that both event A and B have

  to happen

* The addition rules are:

# P(A or B) = P(A) + P(B) ⇒ mutually exclusive (events cannot happen

  at the same time)

# P(A or B) = P(A) + P(B) - P(A and B) ⇒ non-mutually exclusive (if they  

  have at least one outcome in common)

- The union is written as "A∪B" or "A or B"  

- The Both is written as "A∩B" or "A and B"

* Lets solve the question

- The probability P(L) of a visitor riding its largest roller coaster is 30%

∵ P(L) = 30% = 30/100 = 0.3

- The probability P(S) of a visitor riding its smallest roller coaster is 20%

∵ P(S) = 20% = 20/100 = 0.2

- The probability of a visitor riding both roller coasters is 15%

∵ P(L and S) = 15% = 15/100 = 0.15

- To find P(L or S) lets use the rule of non-mutually exclusive

∵ P(A or B) = P(A) + P(B) - P(A and B)

∴ P(L or S) = P(L) + P(S) - P(L and S)

- Substitute the values above to find the probability of a visitor riding

  the largest or the smallest roller coaster

∴ P(L or S) = 0.3 + 0.2 - 0.15 = 0.35

∴ The probability of a visitor riding the largest or the smallest roller

   coaster is 0.35

* The equation is P(L or S) = 0.3 + 0.2 - 0.15

answer:

payment just for service  

→

$

87.12

payment for service including tax

→

$

94.09

explanation:

service only with 20% tip  

→

$

72.6

(

1

+

20

100

)

=

$

87.12

in the opening of the question the word 'service' is associated only with the pretax value.

the closing part of the question asks: how much did she pay for the  

service

−−−−−−  

so technically the answer is  

→

$

72.6

(

1

+

20

100

)

=

$

87.12

however, the intention of the question provider may have been that your answer is to be  

$

87.12

(

1

+

8

100

)

=

$

94.09

to 2 decimal places.

'

payment just for service  

→

$

87.12

payment for service including tax

→

$

94.09

tony b

mar 21, 2017

answer:

trying to explain it another way

explanation:

service charge  

.

→

$

72.60

20% tip  

20

100

×

$

72.60

=

$

14.52

−−−−−−  

←

add

$

87.12

tax  

8

100

×

$

87.12

=

$

6.97

−−−−−  

←

add

$

94.09

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