Why might you want to use a single fixed pulley?
to raise or lower heavy objects
to raise or lower lightweight objects
to reduce the force needed to raise objects
to reduce the weight of lifted objects

A single fixed pulley can be used to raise or lower lightweight objects.

Option b

Explanation:

A pulley is a simple machine tool which is used to make lifting or lowering tasks easy.  A single fixed pulley is a system involving only one pulley fixed on a constant rigid support with a rope wrapped around the wheel. Such a system can be used only to change the direction of  applied force in raising or lowering small, lightweight objects which need minimal work force.

A single fixed pulley system helps only in redirecting the applied force direction by using a rope and wheel assembly. The work done in such a case remains the same and hence it is not preferred to use it in lifting heavy objects. Neither is the required force reduced in case of a single fixed pulley system. A movable pulley helps in achieving (A) and (C).

pecialized keyboards

when jerome paddle in flowing river towards east the net speed of jerome will increase

so the net speed of jerome will be given as

now the speed of paul will be same as it is given as he is running on the ground

so

so here we can say since the speed of jerome is more so he will win the race

now as we know the distance so the time difference is given as

so jerome will reach first and the time difference will be 203.55 s or 3.4 min