Question

A program in Senegal has been reducing infant mortality at a rate
of 11.1% per year. How long will it take for infant mortality
to be reduced by 33%?

Answer 1

solve
.67 = 1(.889)^n
ln .67 = ln (.889^n)
ln .67 = n ln (.889)
n = ln .67/ln .889 = 3.4 years

Answer 2

thank you!