Igualda o desigualdad matemática

Pelle's sister is three years older than pelle the father is 5 times as old as pelle the mother was 28 when the sister was born altogether they are 98 years old how old is pelle?

Afamily has five members. a mom, a dad, two sisters, & a brother. the family lines up single file. what is the probabillity that the mom is at the front of the line

How can i differentiate this equation?