Elba, the answer to this question should be $900.00.
Page 79, last paragraph:
If there is a loss to a pair or set, the company may elect to repair or replace in a way to restore the pair or set to its original value, or to pay the difference between ACV bfore and after the loss.
$1,000 salt & pepper shakers
One shaker is damaged causing the other to only worth $100.
So, to restore the pair of shakers to its original value, the insurer will pay the other $900 ($900 + $100 = $1,000)
I hope this helps,
Clara VanBlargan