Solution:
we have been asked to find how much does one staple weigh?
we are given that 5000 staples weight 15 oz.
In unitary method , we divide the price/weight by quantity to know the price/weight of the one quantity.
Using this concept we can write the weight of 1 staples as below
 5000 staples weight 15 oz.
1 staple weight 
 oz.
1 staple weight 
 oz.