consider the fixed pulley on the wedge

Let the block on the plane be at a distance xAfrom the pulley and let the movable pulley be at a distance xB

Now the idea here is to determine the accleration correlation between the two blocks.

For the block

A

T-(mA)g/2=(mA)aA.........(1)

T is the tension in the string.

for the moving pulley,

Forces are 2T upward and a downward tension T1

If the pulley is assumed to be light then

T1=2T

An upward tension of magnitude 2T thus acts on the hanging block, by newton's third law.

for the block B

(mB)g-2T=(mB)aB.........(2)

Now for the relation between aA and aB,

We have to use the principle of thread length conservation,

i.e. the total length of the thread doesnot change.

The total length of the string

is xA+2(xB)+d1(this is the length wound over the pulley and doesnot

change)=constant

so, differentiating this equation twice yields,(with respect to time)

aA=-2aB

therefore magnitudewise,

aA=2aB.......(3)

so use (1),(2),(3) to get the answers.