Question

The amount of a radioactive substance decreases by 50% every 2.5 days. Right now the

amount of substance is 600 grams. How many grams of the substance will remain 5 days
from now?
A 192
B. 150
C. 96
D.48

Answer 1

Option B

150 grams

Explanation:

Quantity right now is 600 grams

After the first 2.5 days, the substance reduces by 50% that is 50*600 grams/100=300 grams

For the next 2.5 days, the amount of 300 g reduces by 50% that is 50*300 grams/100=150 grams

Adding the first 2.5 days+ next 2.5 days we obtain 5 days ie 2.5+2.5=5 days

Therefore, the amount of substance that remains after 5 days is 150 grams

Answer=150 grams