Radioactive Isotopes and half life

[Zoey Brown]

Homework Statement

If a radioactive isotope ends with 55.5 g, and has a half-life of 2.5 days, how much was

there 8.3 days ago?

Homework Equations

mf=mi(1/2^t/h)

The Attempt at a Solution

the answer i got was 554 g, is it correct?

 

[ehild]

Homework Statement

If a radioactive isotope ends with 55.5 g, and has a half-life of 2.5 days, how much was

there 8.3 days ago?

Homework Equations

mf=mi(1/2^t/h)

The Attempt at a Solution

the answer i got was 554 g, is it correct?

yes, its is correct