Mrs. singh bought 9 folders & 9 notebooks. the cost of each folder was $2.50. each notebook cost $4. write two equivalent expressions & then find the total cost.

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.

Suppose that prices of a gallon of milk at various stores in one town have a mean of $3.71 with a standard deviation of $0.10. using chebyshev's theorem, what is the minimum percentage of stores that sell a gallon of milk for between $3.41 and $4.01? round your answer to one decimal place.

For each phone call robert makes, he pays $0.10 for the first minute and $0.05 for each additional minute. what is the cost for two 5 minute calls ? a $0.60b $0.30c $0.15d $0.45 show work.