Distance and displacement are hardly ever equal.
Remember that 'displacement' is the straight-line distance between the start-point and the end-point, regardless of what path you followed on the way.
So they're equal ONLY when the trip from start to finish was completely in a straight line.
Distance and displacement are generally not equal, as distance is the total path traveled while displacement is the straight-line distance from start to finish. They are only equal when the movement occurs in a straight line. In most scenarios, the distance traveled will be greater than the displacement.
;
[tex]30 \times 3 + 120 \div 40 \times 20 - (15 \times 10) + 20 \\ = 90 + 3 \times 20 - 150 + 20 \\ = 90 + 60 - 150 + 20 \\ = 150 - 150 + 20 \\ = 0 + 20 \\ = 20[/tex]