Question

PLS HELP ME WITH THIS IM GONNA CRY ITS SO HARD....

Arsenic‐74 is used to locate brain tumors. It has a half‐life of 17.5 days. 90 mg were used in a procedure. Write an equation that can be used to determine how much of the isotope is left after x number of half-lives.

Answer 1

Let that be x

Use the general formula used for calculating half-life

`\\ \rm\Rrightarrow A=A_o(0.5)^{(t)/(h)}`

• H is half-life,t is time
• time given x

put values

The equation is

`\\ \rm\Rrightarrow A=90(0.5)^(x/17.5)`