David W. answered 03/07/16
Tutor
4.7
(90)
Experienced Prof
Read and re-read the problem until you understand it and can put it into your own words. How’s this: Starting with x, 10% increase, then 5% decrease is $209.
Let x = price Sam paid
Translate:
"Sam sold his car to David at a profit of 10%"
means Sam sold car for 1.10x
"David sold the car to Rita for $209 at a loss of 5%" means
$209 = 0.95(1.10x)
$209 = 0.95(1.10x) [re-write]
$200 = x
Checking (very important):
Sam sold his $200 car to David at a profit of 10% ($220). David sold the car to Rita for $209, which is a loss of $11 or $11/$220 or 5%). Check!