The death rate of a country fell from 45% to 20% in 30 years. What is the approximate fall in the death rate of the country per year in those 10 years?

This is the solution given by Cracku - is this correct? I don't understand how 1+30r is getting changed to 1+10r

Let the rate of fall be rSo, 45(1+r) 30 = 20 => (1+r) 30 =0.44 Approximate the expression as 1+30r => 1+10r = 0.44 => r = -0.56/10 = -0.056 So, the rate of fall is 5.6%