First draw is 6 out of 10 = 6/10 = 3/5
Second draw is 5 girls out of 9 remaining children = 5/9
Now we multiply the probabilities:
3/5 x 5/9 (you can cancel out the 5's since one is in the numerator and the other is in the denominator. You can also reduce the 3 and 9. The answer is 3/9=1/3
So the chances that the first two selected will be girls is 1/3.