What is 11x11 what is it

How much dextrose 70% must be mixed with dextrose 5% to prepare 1,000 ml of dextrose 20%?

How many sides does a regular polygon have if each exterior angle measure is 45 degrees explain your answer, i really don't understand this.

An office supply company conducted a survey before marketing a new paper shredder designed for home use. in the survey, 80 % of the people who tried the shredder were satisfied with it. because of this high satisfaction rate, the company decided to market the new shredder. assume that 80 % of all people are satisfied with this shredder. during a certain month, 100 customers bought this shredder. find the probability that of these 100 customers, the number who are satisfied is 69 or fewer.