Allowance for receivables

Hello,

Tim is reviewing his trade receivables at the year-end of 31 December 2018. At this date, he had a closing balance in trade receivables of $120,000. The following additional information is provided:
(i) During 2018, he wrote off bad debts of $3,000
(ii) At 01 January 2018 he had an opening balance in the allowance for receivables of $4,500
(iii) At 31 December 2018 he decides to write off a further $2,000 of bad debts
(iv) Having reviewed the remaining trade receivables he required a closing allowance for receivables
as follows:
o Specific allowance of $1,200 against two credit customers
o General allowance of 4% against the remaining credit customers

How do you calculate :
Charge for bad debts
Charge for allowance for receivables
The total charge to Income Statement

Thanks a lot!