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 Author: questioner [ Wed Jan 26, 2011 5:29 pm ] Post subject: GMAT Statistics A salesman's income consists of a commission and a base salary of \$350 per week. Over the past 5 weeks, his weekly income totals have been \$406, \$413, \$420, \$436 and \$395. What must his average (arithmetic mean) commission be per week over the next two weeks so that his average weekly income is \$500 over the 7-week period?A. \$150B. \$245C. \$365D. \$715E. \$730(C) We need to do this problem step-by-step.First, we add up the total income amounts for the past 5 weeks:\$406 + \$413 + \$420 + \$436 + \$395 = \$2070.To average \$500 over 7 weeks, the salesman would need to earn:\$500 × 7 = \$3500.Subtract \$2070 from \$3500 to determine how much he would need to earn, in total, over the next 2 weeks to average \$500 for the 7 weeks:\$3500 – \$2070 = \$1430.Since he will earn \$700 in base salary over the next two weeks, the commission he must earn in the next two weeks is:\$1430 – \$700 = \$730.This is an average of \$730/2 = \$365 per week for these two weeks.The correct answer is choice (C).----------Question Statemtn does not clarify the amount for Salary. It misleads the reader to believe that Commission + Salary is \$350 instead of the just the base salary of \$350.

 Author: Gennadiy [ Wed Jan 26, 2011 5:35 pm ] Post subject: Re: GMAT Statistics Any base salary is a fixed value, while any commission depends on the job results. It's the essence of a commission.Furthermore, the varying commission is clearly the reason for the total income to be \$406, \$413, \$420, \$436 and \$395 over the 5 weeks.

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