An innovative rural public health program is reducing infant mortality in a certain West African country. Pretend the program in Senegal has been reducing infant mortality at a rate 8.7% per year. How long will it take for infant mortality to be reduced by 40%?

Answer 1

start out at 100
60=100(1-.087)^t

.6=.913^t
take log of each side.
log(.6)=t*log(.913)
t= 5.6 years