1 Physics Question

Can someone tell me how to solve this? I’m having trouble with equations:

“A sample contains 20 kg of radioactive material. The decay constant of the material is 0.179 per second. If the amount of time that has passed is 300 seconds, how much of the original material is still radioactive? Show all work.”

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  1. For decay constant λ, the amount left is
    y = N*e^(-kt)
    20e^(-0.179*300) = 9.5*10^-23 kg

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    oobleck
  2. what?

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  3. can you please break it down a little further. Like, explain it to me as if I were a person whose never done it before....

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  4. @oobleck

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  5. (20 kg) x e ^{- 0.179 \times 300}

    = (20 kg ) x e ^{- 53.7}

    = (20 kg) x (4.77 x 10-24)

    = 9.54 x 10-23 kg

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