In the original trolley problem, a train is hurtling down a track and you see that it is going to hit a group of 5 people and will certainly kill them all. However you happen to be standing next to a switch that can divert the train down another track where only a single person would be killed. Would it be right to pull the switch? There is a modified trolley problem involving a fat man. As before, a trolley is hurtling down a track towards five people. You are on a bridge under which it will pass, and you can stop it by dropping a heavy weight in front of it. As it happens, there is a very fat man next to you – your only way to stop the trolley is to push him over the bridge and onto the track, killing him to save five. Should you proceed? Do you see any difference between these two cases that affected your answers to the questions raised?

The Trolley Problem was first introduced to students by Philippa Foot in 1967 and poses an interesting ethical dilemma. To answer it, you need to consider the following two questions. Firstly, is it better to sacrifice one person (the minority) in order to save the lives of the majority? Essentially, this question is asking you to reflect on the value of human life. You must think carefully about whether you believe that one life is worth more or less than the lives of many. 
Secondly, to compound the first problem, you also have to consider the physical aspects of sacrificing a life. In the original version of the Trolley Problem, for example, all you have to do is pull a switch. You are not, in any way, connected to the person who will die. But in the second version, you have to physically push over the man. This means that you are actively involved in sacrificing a life and, for some people, this is much more difficult than simply pulling a switch.
Ultimately, it is your only moral values that will help you to answer these questions. For some people, killing a person is wrong, regardless of the circumstances, while others believe that a sacrifice is sometimes worth making. 
Remember that there are no "right" or "wrong" answers here; the Trolley Problem wants you think deeply about the value of life and reflect on your own ethical code. 
For more information, please see the reference link provided.
https://www.theguardian.com/science/head-quarters/2016/dec/12/the-trolley-problem-would-you-kill-one-person-to-save-many-others