\(\[\begin{align} & Vf=100000 \\ & 1{}^\text{o}trimestre=0,06675 \\ & 2{}^\text{o}\text{ }trimestre=0,0869 \\ & 3{}^\text{o}\text{ }trimestre=0,8 \\ & 4{}^\text{o}\text{ }trimestre=0,07 \\ & juros=0,06 \\ & Vf=\text{ }Vp\text{ }(\text{ }1\text{ }+\text{ }i.1{}^\text{o}trim).(\text{ }1\text{ }+\text{ }i.2{}^\text{o}\text{ }trim)(1\text{ }+\text{ }i.3{}^\text{o}\text{ }trim)(1\text{ }+i.4{}^\text{o}\text{ }trim)\text{ }(\text{ }1\text{ }+\text{ }i.juros\text{ }poupana) \\ & substituindo: \\ & 100000\text{ }=\text{ }Vp.\text{ }\left( 1\text{ }+\text{ }0,06675 \right).(1\text{ }+0,0869).\left( 1\text{ }+0,8 \right)\text{.}\left( 1\text{ }+\text{ }0,07 \right).\left( 1\text{ }+\text{ }0,06 \right) \\ & Simplificando: \\ & Vp=\frac{100000}{1,42} \\ & \text{Portanto:} \\ & Vp=70.410,00 \\ \end{align}\] \)