Mathematics can be tricky so precise definitions are important. Without them there can be confusion which more often then not will generate a wrong answer. With clear precise definitions it is easier to understand the topic. Therefore, it is easier to get the correct answer.
3 and 2/3 hours.
Multiply the number of hours Dominic spent by the scale factor.
Oder of operations is this;
Your identity says ...
... sum of cubes = (sum)³ -3(product)(sum)
... = 4³ -3·1·4
... = 64 -12 = 52
_____
The two numbers are 2±√3, and the sum of their cubes is indeed 52.
1.25 - 0.5 = 0.75
1.25 hours = 1 hour 15 minutes
0.5 hours = 30 minutes
1 hour 15 minutes - 30 minutes = 45 minutes
