1 necklace will therefore cost 34/4 = $8.5 
 
Step-by-step explanation: 
 
She spent between $39 and $59. let us find the average of the amount she spent = 39+59 / 2 = $49. 
 
At an average, she spent $49. 
 
The price of a bracelet is $5 and each bracelet costs the same amount and she bought 3 bracelets = $5 x 3 bracelets each = $15... She spent $15 on the bracelets. 
 
Thus $49 - $15 = amount spent on the 4 necklaces = $34. 
 
4 necklaces cost $34, 1 necklace will therefore cost 34/4 = $8.5