$10,000 down payment for your house if you can invest 2% of your monthly income (yearly income: $67,705) into an account that earns 4% quarterly. Also what is the formula for this? Is it compounded quarterly?

the future value of each deposit = ($67,705 x 1/12 x 0.02) x (1 + 1%)ⁿ = $112.84 x 1.01ⁿ

where n = number of quarters (interest is compounded quarterly)

the effective interest = 1.01⁴ - 1 = 4.06%

Assuming that you are going to make monthly payments, then you would need the number of quarters (n) in order to determine the future value. Since the interest is compounded quarterly, each contribution = $112.84 x 3 = $338.52

For example, if you are planning to save money for 5 years (n = 5 x 4 = 20), then the future value of the investment = $338.52 x 22.019 (FV annuity factor, 1%, 20 periods) = $7,453.87

if you want to calculate the total number of contributions (n):

FV annuity factor, 1%, n? = future value / contribution = $10,000 / $338.52 = 29.5404

since you know the interest rate (1%) you have to look at a future value annuity table and search the n for 29.54. This is approximately 26 periods (FV annuity factor = 29.53).

answer: yes, since the line has a steeper rate of change than the exponential the y-values will be greater and they will only intersect one time.