Answer:
p ^ q
I promise you this is right but it's quite long to explain.
The true answer is
<span>one-half the height between the crest and the trough (check your physics lesson)</span>

is a right triangle with base length 1 and height 8, so the area of

is

.
The average value of

over

is given by the ratio

The denominator is just the area of

, which we already know. The average value is then simplified to

In the

-plane, we can describe the region

as all points

that lie between the lines

and

(the lines which coincide with the triangle's base and hypotenuse, respectively), taking

. So, the integral is given by, and evaluates to,



Answer:
576
Step-by-step explanation:
Do you remember when you were learning about
Least Common Multiple (LCM) ? And you were
wondering what on Earth you would ever need it for ?
THIS IS IT !
The amount of time after 8 PM when the lights will flash
together again is the LCM of 20 seconds and 30 seconds.
Do you remember how to find it ?
... When 20 is prime-factored, you have 2 · 2 · 5 .
... When 30 is prime-factored, you have 2 · 3 · 5 .
... So the Least Common Multiple of 20 and 30 is 2 · 2 · 3 · 5 = 60 .
The lighthouses will flash together again in 60 seconds after 8 PM.
That'll be 8:01 PM.