Applications of
Equations
Lesson 2.3
What are we doing?

Basically, everything we learned
in the previous two lessons will
be applied to real world
situations or unique situations
that will call upon our newly
gained knowledge
Example

The average of two real
numbers is 39.625, and one
number is 1500 times the
reciprocal of the other. Find the
two numbers.
Yet another example

The width of a rectangle is three
times its height. If it has an area
of 60.75 square feet, what are
its dimensions?
Example Number 3

A storage locker in
the shape of a
rectangular prism with
a square floor has a
volume of 70,000
cubic inches. If the
surface area of the
four walls and the top
is 10,000 square
inches, what are the
dimensions of the
locker?
I = PRT {Simple Interest}




I  Interest {fee paid for use of
money}
P  Principal {amount put in}
r  rate {annual interest rate}
t  time {represented in years}
Example

A real estate investment yields a
return of 10% per year and a
certificate of deposit (CD) pays
6% interest per year. How much
of $7500 should be put in the
real estate investment and how
much should be put in the CD to
obtain a return of 7% on the
entire $7500?
Example…again?

A pilot wants to make an 840
mile round trip form Cleveland to
Peoria and back in 5 hours
flying time. There will be a
headwind of 30 mph going to
Peoria, and it is estimated that
there will be a 40-mph tailwind
returning to Cleveland. At what
constant engine speed should
the plane be flown?
All about the examples

A car radiator contains 12 quarts
of fluid, 20% of which is
antifreeze. How much fluid
should be drained and replaced
with pure antifreeze so the
resulting mixture is 50%
antifreeze?
Last One, I promise!

A container in the shape of a
rectangular prism with no top
that has a volume of 650 cubic
inches is to be constructed from
a 28 x 20 inch piece of sheet
metal by cutting squares of
equal size from each corner and
folding up the flaps. What size
square should be cut from each
corner?