Answer:
Sarah has to invest $502,958.58 today.
Step-by-step explanation:
This is a simple interest problem.
The simple interest formula is given by:
In which E is the amount of interest earned, P is the principal(the initial amount of money), I is the interest rate(yearly, as a decimal) and t is the time.
After t years, the total amount of money is:
In this question:

She has to invest P today.

So



Sarah has to invest $502,958.58 today.
Answer:
25 seconds
Step-by-step explanation:
Skydiving.
height (in feet) above the earth=h(t)= -16t^2 + 10,000
the time it would take to fall when h is 0
-16t^2 + 10,000=0
-16t^2=-10000
16t^2=10000
t^2=10000/16=625
t=sqrt 625=25 seconds
Answer: the speed of the current is 9 mph.
Step-by-step explanation:
Let x represent the speed of the current.
A boat can travel 21 mph in still water. If it travels 270 miles with the current. It means that the total speed with which the boat travelled with the current is (21 + x) mph.
Time = distance/speed
Time spent by the boat in travelling 270 miles is
270/(21 + x)
In the same length of time, it travels 108 miles against the current. It means that the total speed with which the boat travelled against the current is (21 - x) mph.
Time = distance/speed
Time spent by the boat in travelling 108 miles is
108/(21 - x)
Since the time is the same, then
270/(21 + x) = 108/(21 - x)
270(21 - x) = 108(21 + x)
5670 - 270x = 2268 - 108x
108x + 270x = 5670 - 2268
378x = 3402
x = 3402/378
x = 9
Answer:
18
Step-by-step explanation:
There are 2+3 = 5 ratio units representing 45 band members, so each ratio unit represents 45/5 = 9 band members.
The 2 ratio units of sixth graders represent 2×9 = 18 sixth grade band members.
Answer:
Step-by-step explanation:
These types of equations are called simultaneous equations and the method we can use to solve these type of equations is either Substitution, Elimination and Graphing.
We use substitution here because it is easier.
Equation 1

Equation 2

Lets take equation 1

This is our equation 3 , now put it inside equation 2.

We found the value of y , now to find the value of x insert the value of y in equation 3

Solved ! See the attached image on both the straight line graphs i have attached for better understanding. Where both the lines intersect each other is our value of (x , y) respectively.