Answer:
7 times during the first 15 minutes
Step-by-step explanation:
Remember that

so

Decompose the numbers 18 and 42 in prime factors
we know that


Find the least common multiple (LCM)
The LCM is

we need to find all multiples of 126 that are less than or equal 900.

therefore
7 times during the first 15 minutes
First compute the whole number of the possibilities :
10*9=90.
Compute the number of favorable possibilities:
There is 5 even numbers. Once we pick an even number,
we pick 5. So the number of the favorable possibilities is 5.
Now we compute the probability like this:
14.99n + 4.99
If we ordered 3 CDS, we need to replace 3 for n.
14.99(3) + 4.99
44.97 + 4.99
49.96
Answer: $49.96
Answer:
(a) Equation: 
(b) 7.5 gallons
Step-by-step explanation:
Given
Current Gas = 10 gallon
Every Hour = -1.25 gallon
Solving for (a): An equation for the scenario
This question represents an Arithmetic Progression and will be solved using the following formula:

Where


Substitute these values in the formula


Collect Like Terms


Solving for (b): In this case, n - 3
Substitute 3 for n in 



<em>7.5 gallon of gas left</em>