How do you solve #4^(-3t)=0.10#?

2 Answers
May 19, 2018

#4^(-3t)=0.10#

Explanation:

#4^(-3t)=0.10#
#ln(4^(-3t))=ln(0.10)#
#-3 t*ln(4)=ln(0.10)#
#t=- ln(0.10)/(3*ln(4))#

May 19, 2018

#t=-log0.1/(3log4)~~0.55#

Explanation:

Given: #4^(-3t)=0.1#

Take logarithms on both sides.

#log(4^(-3t))=log0.1#

#=>-3tlog4=log0.1#

#=>-3t=log0.1/log4#

#t=-1/3log0.1/log4#

#t=-log0.1/(3log4)#

#~~0.55#