Tough and Tricky questions: Word Problems.
A salesman's income consists of commission and base salary. His weekly income totals over the past 5 weeks have been $406, $413, $420, $436 and $395. What must his average (arithmetic mean) income over the next five weeks be to decrease his average weekly income to $400 over the 10-week period? Choose the correct choice from the following options.
A) $385
B) $356
C) $367
D) $376
E) $386
OFFICIAL SOLUTION:   (E) First, we need to add up the wages over the past 5 weeks: $406 + $413 + $420 + $436 + $395 = $2070.   To average $400 over 10 weeks, the salesman would need to earn: $400 × 10 406 +  413 +  420 +  436 +  395= 
<gadget id="calculator">406 +  413 +  420 +  436 +  395</gadget>
<output>2_070</output>
$2070.   To average $400 over 10 weeks, the salesman would need to earn: $400 × 10= $4000.   Subtract $2070 from $4000 to determine how much he would need to earn, in total, over the next 5 weeks to average $400 for the 10 weeks: $4000 – $2070 = $1930.   Dividing $1930 by 5 will give us the amount he needs to earn on average over the next 5 weeks: $1930/5= 
<gadget id="calculator">1930/5</gadget>
<output>386</output>
$386.   The correct answer is choice ($386).
<result>E</result>
Tough and Tricky questions: Word Problems.
A salesman's income consists of commission and base salary. His weekly income totals over the past 5 weeks have been $406, $413, $420, $436 and $395. What must his average (arithmetic mean) income over the next five weeks be to decrease his average weekly income to $400 over the 10-week period?