A researcher wants to investigate whether different forms of exercise can be used to help hyperactive children.A group of 90 children is divided into two groups according to age - those aged 9-12 and those aged 5-9.Within each age group the children are randomly assigned to one of three groups.The first group will just do their normal exercise.The second group will be given an additional exercise routine (moderate) .The third group will be given an additional exercise routine (strenuous) .At the end of a four-month period,parents will be asked to evaluate their children's progress.Identify the factor(s) and any blocking variables and the number of levels for each.

A) Factor: exercise (3 levels) ,Blocking variable: age (2 levels)
B) Blocking variable: exercise (3 levels) ,Factor: age (2 levels)
C) Factor: exercise (3 levels) ,Factor: age (2 levels)
D) Normal exercise and age 5-9,additional exercise (moderate) and age 5-9,additional exercise (strenuous) and age 5-9,normal exercise and age 9-12,additional exercise (moderate) and age 9-12,additional exercise (strenuous) and age 9-12 (6 levels)
E) Factor: Normal exercise,additional exercise (moderate) ,additional exercise (strenuous) (3 levels)

Donna Pierce manages a business that distributes imported woolen fabrics. Donna's business offers a 2.5% cash discount on any amount paid within 10 days of the invoice date. On January 28, a client purchased fabrics priced at $14,500, and on February 1 the client sent in a $10,000 check. Compute the unpaid balance. (This problem involves the partial payment of an invoice within the discount period.)​

Compute the present value in each of the following problems. Use Tables 16-1A&B or 16-2A&B or a calculator.
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a.How much must you invest today at 12% compounded monthly to have $10,000 in 2 years?
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b.Compute the amount that you must deposit today into an account that pays 5% compounded quarterly to have $15,000 in 5 years.

A semicircular arch for a tunnel under a river has a diameter of 80 feet (see figure) . Determine the height of the arch 4 feet from the edge of the tunnel.

A) 36 feet
B) $12\sqrt{11}$ feet
C) $4\sqrt{19}$ feet
D) $4\sqrt{399}$ feet
E) $6$ feet