The answer for the exercise shown above is the first option, which is: <span> f(x)=log(x-3) The explanation is shown below: If you substitute the x in the function for values, you will obtain the graph attached above. As you can see on the mentioned graph, when the variable x has the value 4, the value y is 0. Therefore, you have: </span> f(x)=log(x-3) f(x)=log(4-3) f(x)=log(1) f(x)=0<span> </span>
Compound percentage reduction can be calculated by multiplying the initial number by (1-x)^t where x is the percentage reduction (/100, i.e. 1% reduction is 0.01), and t is the number of times it has reduced.
So: a) Where t is the number of weeks.
We can then just substitute in to work out the final pressure: b) p = 45*0.94^6 = 31psi