The average of 13 numbers is 60. Average of the first 7 of them is 56 and that of the last 7 is 61. Find the 8th number?
Select.
A) 39
B) 83
C) 45
D) 53
E) 64
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 * 56= 
<gadget id="calculator">7 * 56</gadget>
<output>392</output>
392   Sum of the last 7 of them= 7 * 61= 
<gadget id="calculator">7 * 61</gadget>
<output>427</output>
427   So, the 8th number= 427 + 392 - 780= 
<gadget id="calculator">427 + 392 - 780</gadget>
<output>39</output>
39.   39nswer:39
<result>A</result>
The average of 13 numbers is 60. Average of the first 7 of them is 56 and that of the last 7 is 61. Find the 8th number?