First calculate how many possible 2 cards can be dealt, which is 52*51 = 2652. You then divided by 2! (2*1) to get rid of the times where the same 2 cards come, but just in different order (AsKs is the same as KsAs) 2652/2 = 1326. Now figure out how many different possibility are there for Q4o? There are 12:

Qs 4c
Qs 4d
Qs 4h
Qc 4s
Qc 4d
Qc 4h
Qd 4c
Qd 4s
Qd 4h
Qh 4s
Qh 4c
Qh 4d

So the chance of getting Q4o for 1 hand is 12/1326. Now you simply multiply that 3 times to get the chance of getting dealt Q4o for 3 hands in a row:

12/1326 * 12/1326 * 12/1326 =

1728 / 2331473976 = 0.000000741

0.0000741%

Or about 1 out of 1,349,233 (2331473976 / 1728)