A child dies just few hours after birth. Mother cannot conceive further
( His parents runs an NGO , feels deep sorrow for years. They never understood why despite serving society , they had to go through this pain)

A lady get brutally raped.
( She always think forever, what harm I did to the people that I had to undergo this trauma)

A person has been very nice to everyone around. He is doing great business. Very kind guy. One day , his partner frame him for corporate crime and fraud. He has to spent 20 years in jail.

( He live life in shock that despite being good to all, how can Gob be so cruel)

A beggar tries lottery and win jackpot in first attempt.
( He wonders why he didn’t try it ever till age 50. God has been very kind).

There are so many incidents in life, which has no answers.
Law of karma is the only philosophy, which explains it. Over many birth person gets credit or debit out of his Karma.

The law of karma states, that every action performed in life creates another reaction which in turn produces a new counter action. Thus an endless chain of actions and reactions is produced which binds the living entity to his good and bad deeds. This is the way how karma works. It creates an action and another reaction simultaneously and this increases the chain of material activities, keeping the performer in material bondage.

From one life to the next, and from one cosmic creation to the next, the living entity makes a determination to act in a certain way, and then he is entangled in the reactions to his work. After giving up one body, he enters another, and usually he forgets everything about his previous life . The Supersoul in everyone’s heart witnesses one’s past desires and gives one facilities and directions how to fulfill them. In this way, the soul reaps the results of his actions.

Its only law which explain every thing in this universe.

Apply it.