the force E needed to make a machine pull a load is partly constant and partly varies as the load to be pulled itself. when the load is 20g the force needed for 30g load is 2n find the (a) law connecting the load and the force (b) force for the load of 50g

"load is 20g the force needed for 30g load is 2n"

Huh?

Please check for typos.
also
do you mean g (grams or gravity) or kg?