Hi!
So this is an algebra question. We basically want to know what number minus 2 and 1/2 is going to equal 7 and 1/2. An easy way to check for that first number is adding those two numbers together
So we take 2 and 1/2 + 7 and 1/2 , and because they have the same denominator we can add the two numbers . 2 + 7 = 9 and then 1/2 + 1/2 = 1 so 9+ 1 = 10
10- 2 1/2 = 7 1/2
A = $992.00
(I = A - P = $192.00)
Equation:
A = P(1 + rt)
Calculation:
First, converting R percent to r a decimal
r = R/100 = 4%/100 = 0.04 per year.
Solving our equation:
A = 800(1 + (0.04 × 6)) = 992
A = $992.00
The total amount accrued, principal plus interest, from simple interest on a principal of $800.00 at a rate of 4% per year for 6 years is $992.00.
Height of the wall is 27 m.
<u>Explanation:</u>
Let the height of the wall = h
Length of the ladder = 9 m
Angle of elevation = 60°
Ladder rests at 9 m below a vertical wall.
So, length of the wall upto which the ladder rests = h - 9
We know,
Cos Ф = base/ hypotenuse
cos 60° = length of the ladder / height of wall upto which the ladder rests

So,
h - 9 = 18
h = 27
Therefore, height of the wall is 27 m