Answer:
[tex]\frac{11}{39}[/tex]
Step-by-step explanation:
Given,
The number red bulb = 11,
Yellow bulb = 9,
Purple = 7,
Total bulbs = 11 + 9 + 7 = 27,
If two bulbs are taken,
Then, the probability that one bulb is red and one is yellow
[tex]=\frac{^{11}C_1\times ^9C_1}{{27}^C_2}[/tex]
[tex]=\frac{11\times 9}{\frac{27!}{2!\times 25!}}[/tex]
[tex]=\frac{99}{\frac{27\times 26}{2}}[/tex]
[tex]=\frac{99}{27\times 13}[/tex]
[tex]=\frac{11}{39}[/tex]