The unit rate is $7.75 because 46.50 divide by 6 is $7.75
Answer:
10 years and 10 months.
Step-by-step explanation:
The annually interest rate (ia) can be converted by monthly (im) by the equation:
(1 + im)¹² = 1 + ia
(1 + im)¹² = 1 +0.01
(1 + im)¹² = 1.001 (putting ln in both sides)
ln(1 + im)¹² = ln1.001
12*ln(1 + im) = 1.0x10⁻³
ln(1 + im) = 8.33x10⁻⁵(applying "e in both sides)

1 + im = 1.00083
im = 0.00083 = 0.083%
For a investimenting, the final amount (A) can be calculated by:

Where R is the amount invested per month, i is the interest, and n the number of months:
160000 = 400 *
= 400
1.00083ⁿ - 1 = 0.332
1.00083ⁿ = 1.332 (applying ln in both sides)
n*ln1.00083 = ln1.332
8.3x10⁻⁴n = 0.2867
n = 345.4 months
345.4 months *1 yea12 months = 10 years and 10 months.
You got the b part wrong. It would be 4B+4C/2=4D
The formula for the future value A, given annual interest rate r, number of years t, and deposit amount P can be written as
... A = P(1 +r/12)((1+r/12)^(12t) -1)/(r/12)
Filling in the given numbers, you have
... A = 200(1+.0275/12)((1+.0275/12)^(12·39) -1)/(.0275/12) ≈ 167,868.30
The appropriate choice is $167,868.30.
_____
The formula is the one for the sum of a geometric series. It can be useful to consider the last deposit made as the first term of the series.