First, we must convert the mixed fraction 3 1/2 into a simple fraction form:
![3(1)/(2)=(2\cdot3+1)/(2)=(7)/(2)](https://img.qammunity.org/2023/formulas/mathematics/college/9y4rdissf0eue2kyv2xknjj58wxb3l30ug.png)
and now, we can apply the rule of three as
![\begin{gathered} (1)/(4)\text{tsp paprika ------- }(7)/(2)tsp.\text{salt} \\ (1)/(2)\text{tsp paprika ------- x} \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/77l2z5aidc22bz569xspptqk2sqoaocs91.png)
then, x is given by
![x=(((1)/(4))((7)/(2)))/((1)/(2))](https://img.qammunity.org/2023/formulas/mathematics/college/4gbjp0mkkl29e2c74mhtn18mbvicqrlcf4.png)
the x is given by
![\begin{gathered} x=((1\cdot7)/(4\cdot2))/((1)/(2)) \\ x=((7)/(8))/((1)/(2)) \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/rtxe7cntpgy5qdbkpa7j6gf2c85w0qxpl3.png)
now, by appliying the sandwich law, we have
![\begin{gathered} x=(7\cdot2)/(8\cdot1) \\ x=(14)/(8) \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/r4zlbr3a0ic7ybis0mn22x63sepdwj0orn.png)
this last result is equivalente to
![x=(7)/(4)](https://img.qammunity.org/2023/formulas/mathematics/college/k6a90of07xoq56tdto7idzrxbz9q0tvbfn.png)
in other words, we need 7/4 tsp of salt for 1/2 tsp of paprika.