Answer:
The graph is shown below.
The time to make the taste to half is 4.265 s.
Explanation:
Given:
Initial value of the taste is,
![Q_0=1](https://img.qammunity.org/2020/formulas/mathematics/middle-school/eu3sa2rfgi3p6w2tij21m9xolwmoo035eq.png)
Therefore, the quality of taste over time 't' is given as:
![Q(t)=Q_0(0.85)^t\\Q(t)=1(0.85)^t](https://img.qammunity.org/2020/formulas/mathematics/middle-school/xdnnyql0rex607grcfcza5c2t1zda0hxbt.png)
Now, when the taste reduces to half,
![Q=0.5](https://img.qammunity.org/2020/formulas/mathematics/middle-school/ma4xel9zmpkv2kjsn38ealcrl21q2d6xdm.png)
Therefore,
![0.5=1(0.85)^t](https://img.qammunity.org/2020/formulas/mathematics/middle-school/zr12ji4k76zgnww5dpkhzs0z4zmoy1ytob.png)
Taking natural log on both the sides, we get:
![\ln(0.5)=\ln(0.85)^t\\\ln(0.5)=t\ln(0.85)\\t=(ln(0.5))/(\ln(0.85))=4.265\ s](https://img.qammunity.org/2020/formulas/mathematics/middle-school/7aq8jo756o64c0oi2rj46w00w7pzbggzeb.png)
Therefore, the time to make the taste to half is 4.265 s.