Make y the subject to the following questions
3y=c
ay=w
y/c=w
y/a=2c
a=y+p
c=y-k

In this question it basically wants you to leave Y alone in a side of the equation.

In this case,
For 3y=c



For Ay=w



For Y/c=w
Y=cw

For y/a=2c
y=2ac

For a=y+p
y=a-p

For C=y-k
y=C+k

45 this is because of the agarose

2+1=3 that’s your answer