Please help my son dose not understand this .. I’m asking for help ASAP

Some boys and girls were asked if they had a pet. one third of the group were boys. there were 20 boys. 20% of the girls had a pet. boys with a pet : girls with a pet = 1 : 5 i need to know how many girls there are.

What is the 17th term in the arithmetic sequence in which a6 is 101 and a9 is 83

Asquare and an equilateral triangle have the same perimeter. each side the triangle is 4 inches longer than each side of the square. what is the perimeter of the square