Answer:
Total equivalent unit     68,000  units
Explanation:
Item                    equivalent unit
Opening inventory         70% ×  4000         2,800
Fully worked units          100% × 61,000        61,000  Â
Closing inventory         60%×  7000            4200
Total equivalent unit                           68,000
Notes
1. DOC for opening inventory is 70% i.e 100%-30%. Remember that 30% work has been done in the previous period, so the balance is to be done in this current period
2. Fully work represent the units of inventory introduced in the current period and completed in the same period. Meaning 100% work was achieved in the period.
3. Closing work is only 60% completed. This represent work started this period but not yet completed.