Question

(Please answer both parts) Part A

Mary's house cost $500, 000 in the year 2010.
In 2020 she sold it for $900, 000.
Was the change in price an increase or decrease?
Answer:
Part B
What was the percent of change in the price of the house?
Answer:

Answer 1

Part A: It was an increase.

Part B:80%

Explanation:

First, state the info of the problem

Cost Price(CP):$500,000

Selling Price(SP):$900,000

Part A Solution

The SP is higher than the CP so there is a price increase

$900,000>$500,000

Part B Solution

Find price change

Price change equals SP-CP

$900,000-$500,000 equal to $400,000

State CP percent so it will later help in finding percent of price change

CP percent:100%(basic percent for the original cost of item,CP percent is basically 100%)

Cross multiply by comparing amount with percent

So if $500,000 equals 100%

∴$400,000 equals ?(can be represented by variable "x")

Cross-multiplying, we get

$500,000x equals 100%×$400,000(dividing both sides by $500,000)

x equals (400/5)% which further equals 80%

∴The percent of change for the house price was 80%

To confirm

If there was a price increase(Profit),the SP equals CP plus P

SP equals 100% plus 80%:180% ∴SP equals 180%

If 100% equals $500,000

∴180% equals x which is $900,000 after cross-multiplying.

Hope all confusion is now cleared.