$1250
Use the formula i = prt
In this case, we don't know P or Principal amount
i = 400
r = .04 *found by diving 4/100*
n = 8
Set formula to solve for P like: P= i/r(n)
P=400/.04(8)
P= 400/.32
P = 1250
752.4/33 = width
Plug that into your calculator and you'll get the answer.
Justification: legnth times width = area, so area divided by length = width
If you have at least as many equations as your have unknown variables, the 'system' is solvable (unless the equations are copies of eachother).
In this case, isolate one letter and plug it in the other. I'm going for the 2a in the bottom one (it doesn't matter)
2a - 4b = 12 => (divide by two and move the b's to the other side)
a = 6 + 2b. (plug this one into the top equation)
4(6+2b) + 6b = 10 => 24+8b+6b = 10 => 24 + 14b = 10 => 14b = -14 => b=-1
a = 6 + -2 = 4.
So a=4 and b=-1.
Newborn = 18 inches
adult boa = 9 * 18 + 2 = 164 inches
Since all the information is given, then merely put the necessary facts in order.
Had the length of the newborn been unknown, it would have been represented by x.
9x + 2 = 164
9x = 164 - 2
9x = 162
9x/9 = 162/9
x = 18
