Average of five numbers is 61. If the average of first and third numbers is 69 and the average of second and fourth numbers is 69, what is the fifth number ?

$29$

Let the numbers be $A_1 , A_2 , A_3 , A_4 , A_5$

=> $A_1 + A_2 + A_3 + A_4 + A_5 = 61 * 5 = 305$

Also, $A_1 + A_3 = 69 * 2 = 138$

and $A_2 + A_4 = 69 * 2 = 138$

=> $A_5 = 305 - 138 - 138 = 29$

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