Could anybody tell me the answer to this Mathswatch question if possible please?

:)

This is fractions casey shared a pizza with some friends.they each ate 1 third of the pizza. how many people shared the pizza

Which equation represents a proportional relationship that has a constant of proportionality equal to 1/5

20 points for the answer. this is for real , don't put random ! a rectangle has a length of 4 centimeters and a width of 7 centimeters. what is the effect on the perimeter when the dimensions are multiplied by 5? the perimeter is increased by a factor of 5. the perimeter is increased by a factor of 20. the perimeter is increased by a factor of 25. the perimeter is increased by a factor of 100.