Radon enters through the soil into home basements, where it presents a health hazard if inhaled. In the simplest case of radon detection, a sample of air with volume V is taken. After equilibrium has been established, the radioactive decay D of the radon gas is counted with efficiency E over time t. The radon concentration C present in the sample of air varies directly as the product of D and E and inversely as the product of V and t. For a fixed radon concentration C and time t, find the change in the radioactive decay count D if V is doubled and E is reduced by 50%.

Question

anonymous · Answer

D increases by _____%

richyw · Answer

holy cow this one has a lot of letters and I've had a little wine!

anonymous · Answer

C=kDE/Vt

anonymous · Answer

D=(Ct/k)(V/E) 
(Ct/k) is constant

richyw · Answer

are you just showing someone how to do this?

richyw · Answer

or asking for help. Because you are doing it correct.

anonymous · Answer

no its my last hw problem

anonymous · Answer

got the equation dont kno how to get the answer

richyw · Answer

well if your initial equation is correct, which I didn't really check. then all your steps are correct up to here.

richyw · Answer

so change in D is $$\Delta D=D-D_0$$

anonymous · Answer

here is an example from my book

richyw · Answer

ah ok so that's a fractional change.

anonymous · Answer

shouldnt mine be 2/0.5=4 which would be 400%

richyw · Answer

yup.

anonymous · Answer

then my hw program is glitching it says it is wrong

richyw · Answer

wait did you flip your fraction around?

anonymous · Answer

?

anonymous · Answer

i just followed the example

richyw · Answer

oh right I see. yeah I have no idea what is wrong. That answer looks good to me.

anonymous · Answer

it was 300% for some reason