Answer: the whole trip is 160 miles
Explanation:
Let x represent the distance of the whole trip.
so far they have travelled 3/4 of the total distance. It means that they have travelled 3/4 × x = 3x/4 miles
they have travelled 120 miles so far. This means that the 3x/4 miles that they have covered so far is equivalent to 120 miles. Therefore
3x/4 = 120
Cross multiplying with 4
3x/4 × 4 = 120 × 4
3x = 480
Dividing both sides of the equation by 3, it becomes
3x/3 = 480/3
x = 160 miles