[istrydummy]

A sample ( Radiactivity of this sample = 1.61 X10³Bq) contains 17 µg of ATP re isolated from a liver extract to which 2 µg of [³H]-ATP of specific radioactivity 5 KBq/µg had been added and throughly mixed.

How many µg of ATP were present in the original extract?


What i also have: Counts per minute of  the Scintillation counting result from [³H]-ATP sample = 40391.7


What i THINK i know:  2 µg of [³H]-ATP X 5 KBq/µg = 10 KBq  , thus this is now the radiactivity for the 2 µg of [³H]-ATP.

We also know that 17 µg of ATP has an radioactivity of 1.61 X10³Bq

I don't understand what it means by asking me to find µg of ATP present in the original extract.

           
Any help is appreciated. Ta.