Answer :
Answer: [tex]\dfrac{11}{87}[/tex]
Step-by-step explanation:
Given : An automobile manufacturing plant produced 30 vehicles today: 10 were sedans, 9 were vans, and 11 were trucks.
Number of combinations of n things taking r at a time :
[tex]^nC_r=\dfrac{n!}{r!(n-r)!}[/tex]
Number of ways to choose two vehicles out of 30 vehicles :-
[tex]^{30}C_2=\dfrac{30!}{2!(28)!}\\\\=\dfrac{30\times29}{2}\\\\=435[/tex]
Number of ways to choose two trucks out of 11 vehicles :-
[tex]^{11}C_2=\dfrac{11!}{2!(9)!}\\\\=\dfrac{11\times10}{2}\\\\=55[/tex]
Now, the the probability that two trucks will be selected will be :-
[tex]\dfrac{55}{435}=\dfrac{11}{87}[/tex]