How many solutions does this have

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?

Aline has a slope of 1/4 and passes through point (0.4,-1/2). what is the value of the y-intercept?

Find the slope and the y-intercept if there's one and the equation of the line given these two points( 3, 2) and( 3, -4)