Please help! Fan and medal will be given. Thank you in advance!

The half-life of a certain radioactive material is 42 days. An initial amount of the material has a mass of 49 kg. Write an exponential function that models the decay of this material. Find how much radioactive material remains after 8 days. Round your answer to the nearest thousandth.

A. y = 49(1/2)^42x ; 0 kg
B. y = 1/2(1/49)^1/42x ; 0.238 kg
C. y = 49(1/2)^1/42x ; 42.940 kg
D. y = 2(1/49)^1/42x ; 0.953 kg

Question

Please help! Fan and medal will be given. Thank you in advance!

The half-life of a certain radioactive material is 42 days. An initial amount of the material has a mass of 49 kg. Write an exponential function that models the decay of this material. Find how much radioactive material remains after 8 days. Round your answer to the nearest thousandth. 

A. y = 49(1/2)^42x ; 0 kg
B. y = 1/2(1/49)^1/42x ; 0.238 kg
C. y = 49(1/2)^1/42x ; 42.940 kg
D. y = 2(1/49)^1/42x ; 0.953 kg

priyar · Answer

Do u know any formulas related to this problem?

ray1998 · Answer

Honestly, no. I'm way behind in math and am hardly passing. This is just me trying to catch up and get to a passing grade.

priyar · Answer

but this is a chemistry problem...

blacksteel · Answer

So we know that if f(t) is the amount of material remaining,
f(0) = 49 and f(42) = 0.5*49

Then our function should be one that passes through (0,49) and (42, 24.5). Which equation is this true for?

ray1998 · Answer

No, it's for Algebra 2 @priyar

priyar · Answer

oh ok it can be solved either way though!

ray1998 · Answer

C?

blacksteel · Answer

Exactly!

ray1998 · Answer

Oh, okay. Thanks :) @priyar

ray1998 · Answer

Oh! I got it right? @Blacksteel

blacksteel · Answer

Yup. Good job =)

ray1998 · Answer

Thank you so much!!!!