It was complicated but I did it
.15(pi)=24-68(0) that is the answer hope it helps
well, let's split the hours in minutes, so since 1 hr is 60 minutes, so he can walk 2.833 miles in 60 minutes, well, 3 hrs is 3*60 = 180 minutes, then we add 15 minutes, that's 195 minutes.
if he can walk 2.833 miles in 60 minutes, how long will it be for 195 minutes?
![\bf \begin{array}{ccll} miles&minutes\\ \cline{1-2} 2.833&60\\ x&195 \end{array}\implies \cfrac{2.833}{x}=\cfrac{60}{195}\implies \cfrac{2.833}{x}=\cfrac{4}{13} \\\\\\ 36.829=4x\implies \cfrac{36.829}{4}=x\implies 9.20725 = x](https://tex.z-dn.net/?f=%5Cbf%20%5Cbegin%7Barray%7D%7Bccll%7D%20miles%26minutes%5C%5C%20%5Ccline%7B1-2%7D%202.833%2660%5C%5C%20x%26195%20%5Cend%7Barray%7D%5Cimplies%20%5Ccfrac%7B2.833%7D%7Bx%7D%3D%5Ccfrac%7B60%7D%7B195%7D%5Cimplies%20%5Ccfrac%7B2.833%7D%7Bx%7D%3D%5Ccfrac%7B4%7D%7B13%7D%20%5C%5C%5C%5C%5C%5C%2036.829%3D4x%5Cimplies%20%5Ccfrac%7B36.829%7D%7B4%7D%3Dx%5Cimplies%209.20725%20%3D%20x)
Sin2x=2sinxcosx, cos2x=1-2sin^2x
sin(2x)+cos(3x)=2sinxcosx+cos(x+2x)
cos(x+2x)=cosx(1-2sin^2(x))-sinx2sinxcosx
sin(2x)+cos(3x)=2sinxcosx(1-sinx)+cosx(1-2sin^2(x))