The average of 13 numbers is 59. Average of the first 7 of them is 57 and that of the last 7 is 61. Find the 8th number?  Select:
A) 59
B) 83
C) 45
D) 53
E) 64
Sum of all the 13 numbers = 13 * 59= 
<gadget id="calculator">13 * 59</gadget>
<output>767</output>
767   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 - 767= 
<gadget id="calculator">427 + 399 - 767</gadget>
<output>59</output>
59.   59nswer:59
<result>A</result>
The average of 13 numbers is 59. Average of the first 7 of them is 57 and that of the last 7 is 61. Find the 8th number?