Advanced Excel Help …”I’m Stumped”

I need a formula to find all the same acct numbers from one column and their matching data in the adjacent coliumn, them Sum and populate a different worksheet. i.e.,

Col A Col B
2545 $25.00
2658 $65.00
2545 $25.00
2165 $13.00
Result for #2545 would be $50.00

Anyone who could help would save me a TON of work!!!