Maths question, Oundle School past paper

[Apple33]

My son was given this question and I try to figure out but I have such a mental block!

Q) A property owner sold two terraced houses each at £99 000 each. Based on what he had paid for them, the profit on one was 10% and the loss on the other was 10%. Overall, did the property owner make a profit or loss? Calculate the amount of profit or loss.

from mark schemes, I know the answer is: A loss of £2,000 but I don't know how to calculate it.
Can you please help me.
Many thanks

[sbarnes]

Classic percentage question..I'll try and explain how I have taught my son..Start with a triangle format as below..


New Number

Old Number Multiplier

The new number in the example is £99000 (the sold price of the house)

For the profit, the multiplier is 1+0.1=1.1 (100% is 1, and so 10% profit, is 0.1 as a decimal)

For the loss, the multiplier is 1-0.1=0.9 (100% is 1, therefore loss of 10% is 0.1 as a decimal and is subtracted because of reduction)

Therefore, the cost of the house prior prior to sale with 10% profit was £99000/1.1= £90000 (use the triangle)

The cost of the house prior to sale with 10% loss was £99000/0.9= £110000


So for profit, he makes £9K

and for loss, he loses £11k

Overall loss is £2k (11k-9k=2k)

This is my method and works every time;

Hope you follow the logic

[sbarnes]

on the last line of the triangle, there should be a space between old number and the multiplier, the format has not been respected when I have submitted, think of a triangle with all 3 in each corner of the triangle

[Apple33]

Many thanks for your help