The average of 13 numbers is 60. Average of the first 7 of them is 57 and that of the last 7 is 61. Find the 8th number?
Choose one:
A) 46 B) 28 C) 25 D) 22 E) 29
Sum of all the 13 numbers = 13 * 60= 
<gadget id="calculator">13 * 60</gadget>
<output>780</output>
780   Sum of the first 7 of them= 7 * 57= 
<gadget id="calculator">7 * 57</gadget>
<output>399</output>
399   Sum of the last 7 of them= 7 * 61= 
<gadget id="calculator">7 * 61</gadget>
<output>427</output>
427   So, the 8th number= 427 + 399 - 780= 
<gadget id="calculator">427 + 399 - 780</gadget>
<output>46</output>
46.   46nswer: 46
<result>A</result>
The average of 13 numbers is 60. Average of the first 7 of them is 57 and that of the last 7 is 61. Find the 8th number?