If the average (arithmetic mean) of seven consecutive integers is 20, then the product of the greatest and least integer is
Choose one
A) 343 B) 393 C) 363 D) 391 E) 409
n = smallest number   n+6 = largest number   (n + n + 6)/2 = 20   =&gt; (2n+6)/2 = 20   =&gt; n + 3 = 20   =&gt; n = 17   So Product of n and n+6 = (17) (23)   = 391   Answer - 391
<result>D</result>
If the average (arithmetic mean) of seven consecutive integers is 20, then the product of the greatest and least integer is