The answer is indeed 3,725.90. The reason why is because <span>with each adjustment, you take the remaining balance and calculate a fixed rate loan for the remaining time period at the new rate. When you follow that procedure with the data you already have, you get that answer.</span>
So this is going to be alot of writing to show my thinking but ill bold the answer.
1,1
1,2
1,3
1,4
1,5
2,1
2,2
2,3
2,4
2,5
3,1
3,2
3,3
3,4
3,5
4,1
4,2
4,3
4,4
4,5
5,1
5,2
5,3
5,4
5,5
next ill mark all the ones that equal 4 or 8 when added together, with an x
1,1
1,2
x1,3
1,4
1,5
2,1
x2,2
2,3
2,4
2,5
x3,1
3,2
3,3
3,4
x3,5
4,1
4,2
4,3
x4,4
4,5
5,1
5,2
x5,3
5,4
5,5
that is 6 (that equal 4 or 8) out of 25
so your ratio would be 6:19
"Will is twice as old as Jill."
Jill's age . . . . . J
Will's age . . . . 2J .
"Three years ago . . .
Jill's age then . . . . . J - 3
Will's age then . . . . 2J - 3
". . . Jill's age then was 2/5 of Will's age then."
J - 3 = (2/5) (2J - 3)
Multiply
each side by 5 : 5J - 15 = 2 (2J - 3)
Divide
each side by 2 : 2.5 J - 7.5 = 2J - 3
Subtract 2J
from each side: 0.5 J - 7.5 = -3
Add 7.5
to each side: 0.5 J = 4.5
Multiply
each side by 2 : J = 9
Jill is 9 y.o. now.
Will is 18 y.o. now.
Consider the function

, which has derivative

.
The linear approximation of

for some value

within a neighborhood of

is given by

Let

. Then

can be estimated to be

![\sqrt[3]{63.97}\approx4-\dfrac{0.03}{48}=3.999375](https://tex.z-dn.net/?f=%5Csqrt%5B3%5D%7B63.97%7D%5Capprox4-%5Cdfrac%7B0.03%7D%7B48%7D%3D3.999375)
Since

for

, it follows that

must be strictly increasing over that part of its domain, which means the linear approximation lies strictly above the function

. This means the estimated value is an overestimation.
Indeed, the actual value is closer to the number 3.999374902...