Jim and Ann bought a house with a down payment of 9000 and a
Solution
Purchase cost of house = $ 150000; Down payment = $9000; Loan amount = $141000; Interest rate = 4.8% p.a. or monthly rate of (4.8%/12) = 0.40%; tenure = 25 years or 300 months
Closing cost at time of purchase = 1.4% * 150000 = $2100
Monthly mortgage payment = Loan amount * [r * (1+r)t]/[(1+r)t - 1] ; where r is the applicable monthly rate and t is the tenure in months. Plugging in the values we get:
Monthly mortgage payment = 141000 * [0.40% * (1+0.40%)300] / [(1+0.40%)300 - 1] = 807.93
When the house is sold after 2 years, the residual loan balance will be :
Loan Amount * [(1+r)t - (1+r)k] / [(1+r)t - 1] ; where k is the time period in months at which we require the residual balance and in this case k - 24 months. Plugging in the values we get:
141000 * [(1+0.40%)300 - (1+0.40%)24] / [(1+0.40%)300 - 1] = 134,868.40
Hence the equity in the house has grown by (141000 - 134868.40) = 6131.6
The selling costs = 4% * 150000 = 6000
Now lets look at all the costs involved in buying and holding the house for 24 months:
Purchase Equity : 9000
Increase in equity at the time of sale = 6131.6 or monthly (6131.6/24) = 255.48
Purchase costs = 2100 or monthy (2100/24) = 87.5
Sale costs = 6000 or monthly (6000/24) = 250
Monthly mortgage payment = 807.93
Total monthly costs over 2 years = (87.5 +250 + 807.93) - 255.48 = 889.95
