The average of 13 numbers is 60. Average of the first 7 of them is 54 and that of the last 7 is 61. Find the 8th number?
Pick:  A) 25  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 * 54= 
<gadget id="calculator">7 * 54</gadget>
<output>378</output>
378   Sum of the last 7 of them= 7 * 61= 
<gadget id="calculator">7 * 61</gadget>
<output>427</output>
427   So, the 8th number= 427 + 378 - 780= 
<gadget id="calculator">427 + 378 - 780</gadget>
<output>25</output>
25.   25nswer:25
<result>A</result>
The average of 13 numbers is 60. Average of the first 7 of them is 54 and that of the last 7 is 61. Find the 8th number?