Answer:
$20,000  
Step-by-step explanation:
Balance carried forward (c/f)   = $ 50,000
Cash receipts (add)                  = $  48,000
Cash disbursement (subtract) = $ (68,000)
Cash balance                           = $  30,000
Since the cash  balance is  $  30,000, the company will need to borrow  $20,000  during July in order to align with company policy.
NB : Please note that  $ (68,000) mean - $ 68,000.