hi guys i have problem with this question

Recall that a variable y satistfies exponential decay if t satisfies the dMferential equation y = k*y(where k<0).

where C represents the initial value of yat time t 0. Typicaly the value of kis found from knowing the value of y at some other time

isyCte(k*)

Use this information to solve the folowing Calculusium is a radioactve material with a halt-ufe of 40 years. fyou start out with 100 . after how many years wll you be down to

30 g?

-Recal the halt-ife of a substance is the amount

o decay to haif its original value!