Question

The average of 5 numbers is 7 When three new number are added, the average of the eight numbers is 8.5. The average of the three new numbers is nearly

• A. 15
• B. 17
• C. 11
• D. 14

Answer 1

The correct option is B 17

$=\frac{7\times 5+3\overline{x}}{7+3}=8.5$
$\Rightarrow 3\overline{x}=85-35$
$\Rightarrow \overline{x}=\frac{50}{3}=17$