Explanation:
The month-end adjusting entry is as follows
Supplies expense A/c Dr $2,500
To Supplies A/c $2,500
(Being supplies account is adjusted for $2,500)
The supplies expense is calculated below
= Supplies balance + purchase made - supplies on hand
= $1,200 + $2,900 - $1,600
= $2,500
Basically we debited the supplies expense account and credited the supplies account for $2,500