Hey can someone explain these to me

Twenty-five percent of the customers entering a grocery store between 5 p.m. and 7 p.m. use an express checkout. consider five randomly selected customers, and let x denote the number among the five who use the express checkout.

Me complete this proof! prove that a quadrilateral is a square. me with the steps for this proof.

The square pyramid has a volume of 441 cubic inches. what is the value of x? 1/7x is the height x is the base