The number of wolves in the wild in the northern section of

The number of wolves in the wild in the northern section of the Cataragas county is decreasing at the rate of 3.5% per year. Your environmental studies class counted 80 wolves in the area. Between what two years will the population be between 20 and 30 wolves? 17.) Compact fluorescent light bulbs save energy when compared with traditional incandescent bulbs. Our green energy campaign includes efforts to get local residents to exchange their incandescent bulbs for fluorescent bulbs. Initially 300 households make the change. Market studies suggest that, in the absence of limiting factors, we could increase that number by 20% each month. In our target area there are 275,100 households. Make a logistic model that gives the number of households converting to fluorescent bulbs after t months. 18.) The table below shows the median American family income I by years since 1980. a.) Use linear regression to find the model that best fits this data. b.) Use the model to predict the median income in 1987.

Solution

16) 20=80(1-3.5/100)^t or,1/4=(1-7/ 200)^t or,t=ln4/ln200-ln193=2x.30103/ln2+2-ln193=.60206/2.30103-2.2856 =28yrs 30=8o(1-3.5/100)^t or3/8=(1-7/200)^t or t=ln3-ln8/ln200-ln193=0.42587/0.0247=18 ANSbetween 18 to 28yrs 17)275100=300+300x20/100+300x20/100x20/100+---------tyrs or275100=t/2{2x300+(t-1)x20/100} or275100=t/2(600+t-1/5) or 275100=t(2999+t) ANS