Question

please read the heading and answer the question picturised

Answer 1

cardinality = no of elements in a set
$- 7 < 3b - 1 < 2$
$- 6 < 3b < 3$
$- 2 < b < 1$
A4 = {-2,-1,0,1}

Answer 2

first answer my question A told B ,“when i was as old as your now, then your age was four year less half of my present age". If the sum of present age of A and B is 61 years , what B's present age?(in year)