Algebra - word problem

P

pboland

New member
Joined
Feb 7, 2006
Messages
41
A study found that among those who never or almost never drank coffee, the occurrence of liver cancer ws 547.2 cases per 100,000 people over a ten year period. For daily coffee dringers the risk was 214.6 cases per 100,000. Find the percent change in liver cancer risk for coffee drinkers.
%change=new-old/old(100%)
547.2/100,000 = .055
214.6/100,000=.002
(.055-.002)/.002*100%
.053/.002(100%)=26.5(100%)=2650%
Is this done correctly?
 
pboland said:
A study found that among those who never or almost never drank coffee, the occurrence of liver cancer ws 547.2 cases per 100,000 people over a ten year period. For daily coffee dringers the risk was 214.6 cases per 100,000. Find the percent change in liver cancer risk for coffee drinkers.
%change=new-old/old(100%)
547.2/100,000 = .055
214.6/100,000=.002
(.055-.002)/.002*100%
.053/.002(100%)=26.5(100%)=2650%
Is this done correctly?
Click to expand...

You have the correct format -- %change = (original%-new%)/original% -- but you misfigured. If 547.2/100,000 = .055, then 214.6/100,000 cannot be merely .002.
 
Re: algebra

pboland said:
Every time I divide 214.6/100,00 I still get .002
Click to expand...

To determine a percentage of increase or decrease, calculate

original value - new value
original value

Work with the original value (547.2) and the new value (214.6) and change the answer you get to a percentage. You don't need to use the 100,000 in figuring the per cent of change. A change from a higher original value to a lower new value is clearly going to be a percentage decrease.
 
algebra

547.2-214.6/547.2(100%)=
332.6/547.2(100%)=0.6(100%)=
60.782 or 61%
 
Right on.

BTW The original error was in 547.2/100000 = .005472 and wrong original value.
(.005472-.002146)/.005472 would have given the same answer.
 
You must log in or register to reply here.
Top