A radioactive substance takes 20 min to decay 25%. How much time will be taken to decay 75% [Orissa JEE 2005]

A radioactive substance takes 20 min to decay 25%. How much time will

1.	A radioactive substance takes 20 min to decay 25%. How much time will be taken to decay 75% [Orissa JEE 2005]
A.	96.4 min
B.	68 min
C.	964 min
D.	680 min
Answer» B. 68 min

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A radioactive substance takes 20 min to decay 25%. How much time will be taken to decay 75% [Orissa JEE 2005]

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