
Hope you could get an idea from here.
Doubt clarification - use comment section.
Answer:
first, u need to know the formula for compound interest, which is:

where A is the final amount
P- initial amount
r- percent compounded(interest)
and
n- number of years
so
we have

3.8/100 = 0.038
1+0.038 =1.038
1.038^4 = 1.160885573136
475 * 1.160885573136 = 551.4206472396
approximately $551.42
If the side lengths of B are 2x as long as the side lengths of A then the volume of B should be the volume of A^2
216^2=46,656
46,656-216=46,440
This can be more easily displayed with smaller numbers
If cube X were 2*2*2 then the volume would be 8
If cube Y were 4*4*4 then the volume would be 64
8(volume of cube X)^2=64(volume of cube Y)
A. solve for 1 variable
let's solve for x in 2nd equation
add 2y to both sides
x=2y+4
sub 2y+4 for x in other equation
3(2y+4)+y=5
6y+12+y=5
7y+12=5
minu12 both sides
7y=-7
divide 7
y=-1
sub back
x=2y+4
x=2(-1)+4
x=-2+4
x=2
(2,-1)
B. eliminate
eliminate y's
multiply first equation by 2 and add to first
6x+2y=10
<u>x-2y=4 +</u>
7x+0y=14
7x=14
divide by 7
x=2
sub back
x-2y=4
2-2y=4
minus 2
-2y=2
divide -2
y=-1
(2,-1)
(2,-1) is answer