The answer is going to be 2*sqrt(5). You have to split it into perfect squares for it to be simplified... so in this case, I had sqrt(4*5) because sqrt(4) can be simplified... so your answer would be sqrt(4)*sqrt(5) or 2sqrt(5)
He starts out with the weight of 160, at the end of those 12 months he weighs 232. if you subtract 160 and 232 the approximate rate of change should be 72