Word problem. Pre-Cal.

An adult takes 400 mg of ibuprofen. Each hour, the amount of ibuprofen in the person's system decreases by about 29%. How much ibuprofen is left after 6 hours?

Decreasing: A=P(1-r)^x

Question

Word problem. Pre-Cal. 

An adult takes 400 mg of ibuprofen. Each hour, the amount of ibuprofen in the person's system decreases by about 29%. How much ibuprofen is left after 6 hours? 

Decreasing: A=P(1-r)^x

anonymous · Answer

Can someone please tell me if I am on the right track?? I got: A=400(1-.29)^6 = .128100283921

anonymous · Answer

yes. but multiply by 400 ;)

anonymous · Answer

thank you :) but what do I multiply by 400? :o

anonymous · Answer

OH hahaha I see so I got 51.2401135684. would that mean that after 6 hours 51 mg ibuprofen is left?

anonymous · Answer

lol ya C:

anonymous · Answer

thanks, you're awesome! :) i have 2 more problems similar to this, can you help me with those? :)