Answer :
ok
A=P(1/2)^(t/h)
A=amount final
P=initial amount
t=time elapsed
h=time of half life
so
given h=13
and initial =48g
and final is 12g
12=48(1/2)^(t/13)
divide both sides by 48
1/4=(1/2)^(t/13)
what a coincidence
(1/2)^2=(1/2)^(t/13)
so
2=t/13
26=t
26 hours have passed
A=P(1/2)^(t/h)
A=amount final
P=initial amount
t=time elapsed
h=time of half life
so
given h=13
and initial =48g
and final is 12g
12=48(1/2)^(t/13)
divide both sides by 48
1/4=(1/2)^(t/13)
what a coincidence
(1/2)^2=(1/2)^(t/13)
so
2=t/13
26=t
26 hours have passed