Question 1108113
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After inserting 4 arithmetic means between 3 and 23 you will have 5 (five) intervals of equal lengths, 
that together comprise the interval of the total length of  23-3 = 20 units.


So, each elementary interval is  {{{20/5}}} = 4  units long.


Hence, the A.M. to be inserted are 

    3  +  4 =  7,

    7  +  4 = 11,

    11 +  4 = 15,

    15 +  4 = 19.
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