Answer:
The original length was 41 inches and the original width was 16 inches
Step-by-step explanation:
Let
x ----> the original length of the piece of metal
y ----> the original width of the piece of metal
we know that
When squares with sides 5 in long are cut from the four corners and the flaps are folded upward to form an open box
The dimensions of the box are
The volume of the box is equal to
so
simplify
-----> equation A
Remember that
The piece of metal is 25 in longer than it is wide
so
----> equation B
substitute equation B in equation A
solve for y
Solve the quadratic equation by graphing
using a graphing tool
The solution is y=16
see the attached figure
Find the value of x
therefore
The original length was 41 inches and the original width was 16 inches
In mathematical form, it would be: 2x ≥ 40
x ≥ 20
Hope this helps!
Current amount in account
P=36948.61
Future value of this amount after n years at i=11% annual interest
F1=P(1+i)^n
=36948.61(1.11)^n
Future value of $3000 annual deposits after n years at i=11%
F2=A((1+i)^n-1)/i
=3000(1.11^n-1)/0.11
We'd like to have F1+F2=280000, so forming following equation:
F1+F2=280000
=>
36948.61(1.11)^n+3000(1.11^n-1)/0.11=280000
We can solve this by trial and error.
The rule of 72 tells us that money at 11% deposited will double in 72/11=6.5 years, approximately.
The initial amount of 36948.61 will become 4 times as much in 13 years, equal to approximately 147800 by then.
Meanwhile the 3000 a year for 13 years has a total of 39000. It will only grow about half as fast, namely doubling in about 13 years, or worth 78000.
Future value at 13 years = 147800+78000=225800.
That will take approximately 2 more years, or 225800*1.11^2=278000.
So our first guess is 15 years, and calculate the target amount
=36948.61(1.11)^15+3000(1.11^15-1)/0.11
=280000.01, right on.
So it takes 15.00 years to reach the goal of 280000 years.
