15(1+0.6/4)^4t = 30e^-0.25t, solve for t

x =

                ≈ 0.856

Step-by-step explanation:

 15(1 + )⁴ˣ = 30e⁻°²⁵ˣ

 15(1.15)⁴ˣ = 30e⁻°²⁵ˣ

÷30           ÷30          

0.5(1.15)⁴ˣ = e⁻°²⁵ˣ

ln[0.5(1.15)⁴ˣ] = ln[e⁻°²⁵ˣ]

ln 0.5 + ln(1.15)⁴ˣ = -0.25x

ln + 4x ln(1.15) = -0.25x

4x ln(1.15) + 0.25x = -ln

x(4 ln(1.15) + 0.25) = -ln 0.5

x =

  ≈ 0.856

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