Answer:
24.12 days
Explanation:
First off, let's find out how many decays the compound ; iodine131 undergoes to get to 17.5 percent of its original value.
Half life is simply the time required for a quantity to reduce to half of its initial value.
The half-life of iodine-131 is 8.04 days.
100% - 50% (First Half life)
50% - 25% (Second Half life)
25% - 17.5% (Third Half life)
This mwans i would take three halff lives;
Time requred = 3 * Half life = 3 * 8.04 days = 24.12 days
