Help me with this please.

With finding limits of multi variable !

The area (a) of a circle with a radius of r is given by the formula and its diameter (d) is given by d=2r. arrange the equations in the correct sequence to rewrite the formula for diameter in terms of the area of the circle.

Ashley recently opened a store that sells only natural ingredients. she wants to advertise her products by distributing bags of samples in her neighborhood. it takes one person 22 minutes to prepare one bag. how many hours will it take to prepare 900900 bags of samples if ashley and 55 of her friends do the work?