Answer:
The rate of the current is 2 miles per hour.
Step-by-step explanation:
Let us assume that the rate of the river is v miles per hour.
The speed of the boat is 12 miles per hour.
Let us assume also that the boat can go 21 miles in t hours in the downstream and 15 miles upstream at the same time i.e. t hours.
So, from the condition given we can write that
......... (1), and
......... (2)
Now, adding those two equations we get
⇒
hours
Now, from equation (1), we get,
⇒ v = 2 miles per hour
Therefore, the rate of the current is 2 miles per hour. (Answer)
Answer:
The number of minutes advertisement should use is found.
x ≅ 12 mins
Step-by-step explanation:
(MISSING PART OF THE QUESTION: AVERAGE WAITING TIME = 2.5 MINUTES)
<h3 /><h3>Step 1</h3>
For such problems, we can use probability density function, in which probability is found out by taking integral of a function across an interval.
Probability Density Function is given by:

Consider the second function:

Where Average waiting time = μ = 2.5
The function f(t) becomes

<h3>Step 2</h3>
The manager wants to give free hamburgers to only 1% of her costumers, which means that probability of a costumer getting a free hamburger is 0.01
The probability that a costumer has to wait for more than x minutes is:

which is equal to 0.01
<h3>
Step 3</h3>
Solve the equation for x

Take natural log on both sides

<h3>Results</h3>
The costumer has to wait x = 11.53 mins ≅ 12 mins to get a free hamburger
Answer:
D!!!
Step-by-step explanation:
you have to make a table to see that randy has run 3 miles.!!!
Answer:
The answer is 81.
Step-by-step explanation:
Since the power of 4 is even, the result will be positive.

Simplify.

<u>hence</u><u>,</u><u> </u><u>the</u><u> </u><u>answer</u><u> </u><u>is</u><u> </u><u>Option</u><u> </u><u>A</u><u>)</u><u> </u><u>81</u><u>.</u>