Pls help, sorry for the trouble

Question

Link to image of the problem

Thank you!

Answer 1

Distance this is area under velocity graph: d₁ = 20m/s·15s/2 = 150m; d₂ = 20m/s·5s·/2 + 20m/s·(t - 20)s;

d₁ = d₂; 150 = 50 + 20(t - 20); t - 20 =5; t = 25 s

Answer 2

Distance is the area under the curve of velocity. From 0 to 15 velocity is positive so the object is moving away from origin. After that it has negative velocity and moving back to origin. at the point that positive area is equal to negative area, the object will be at origin again which is at t=25 by easy geometrical calculations.

Hence t is between 20 and 30 as in first choice.