00:01
Hello.
00:03
So in this question we can solve this problem using the exponential decay formula, which is q of t.
00:10
So this is the quantity of radiative material remaining after t years.
00:16
It's going to be q not, which is the initial quantity.
00:20
And then we have 1 minus r into t.
00:24
So r is the rate of decay time.
00:27
It's in years.
00:30
So now we can find q not.
00:38
Okay.
00:41
So we'll have 1 minus r into t.
00:41
So we have a rate of decay time.
00:41
It's in years.
00:41
So now.
00:41
So now, we can find.
00:41
So we can.
00:41
So we can.
00:41
So we can.
00:41
So we can.
00:41
So we we can try some substitution here because we've been giving q of t to be 1 .52.
00:48
It's q0, we have 1 minus.
00:51
The rate is 0 .18 times 4.
00:59
So we have 1 .52 here...