Linq query - compare 2 datatables and fetch matched row dt1 specific cell value and update the dt2 with retrived value

how to compare 2 datatables and fetch matched row dt1 specific cell value and update the specific cell in dt2 with retrived value in matched row - using linq query

Kindly help me if im using foreach for bulk data its is taking a long time as it need to iterate

@swetha_k