Tonic

One package tonic consumes Mom for 12 weeks and the daughter for 14 weeks. They use the same cream together for four weeks and then only their daughter. How many weeks endured tonic to daughter then?

Final Answer:

x =  5.3333 t

Step-by-step explanation:

$$\begin{gathered} d=\frac{1}{12}+\frac{1}{14}=\frac{7}{84}+\frac{6}{84}=\frac{7+6}{84}=\frac{13}{84}\doteq 0.1548 \\ 4\cdot d+\frac{x}{14}=1 \\ 4\cdot 0.1547619047619+\frac{x}{14}=1 \\ 4\cdot 0.1547619047619+x/14=1 \\ x=5.333333 \\ x=\frac{5.33333333}{1}=5.33333333 \\ x=\frac{16}{3}\doteq 5.333333=5.3333\text{t} \end{gathered}$$

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