Answer:
t = 15d
Explanation:
You must first know that 1 week = 7days
If Sophie practices the piano 105 minutes in 1 week, this can be expressed as;
105 minutes = 7days
to calculate the total time t that she practices for any number of days, d, we will say;
t minutes = d days.
Solving both expression;
105 minutes = 7days
t minutes = d days.
Cross multiply;
7 * t = 105 * d
7t = 105d
Divide both sides by 7;
7t/7 = 105d/7
t = 15d
Hence a proportional equation for t in terms of d that matches the context is expressed as t = 15d