Calculating Common Velocity of Two Identical Blocks After Collision

[dalcde]

Homework Statement

Two identical blocks of the same mass travel at velocities of 3v and 2v on a smooth surface as shown (same direction).
Two blocks move together after collision. What is their common velocity?

Homework Equations

Conservation of momentum

The Attempt at a Solution

Let v' be the common velocity.

3mv+2mv = 2mv'
v'= 2.5v

Therefore the veloctiy is 2.5v. Answer given is 1.5v.

 

[Filip Larsen]

From the information given the answer should be 2.5 v.

 

[dalcde]

Thank you