Formula for probability is given below as,
[tex]\text{Probability = }\frac{required\text{ outcomes}}{possibl\text{e ourcomes}}[/tex][tex]\begin{gathered} \text{Prob that a skater aged 12 is injured should be taken as P(L)} \\ P(L)=0.9 \\ \text{Prob that a skater is wearing in-line skates be taken as P(M)} \\ P(M)=0.2 \\ \text{Prob that a skater is aged 12 and wearing in-line skates is P(N)} \\ P(L\text{ AND M) = 0.1} \end{gathered}[/tex]
To find the probability that an injured skater was age 12 or wearing an in-line skates will be,
[tex]\begin{gathered} P(L\text{ OR M) =P(L) + P(M) - P(L AND M)} \\ \end{gathered}[/tex]
Substituting all the probabilities into the question above,
[tex]P(L\text{ OR M) =0.9 + 0.2 - 0.1 = 1}[/tex]
Hence, the answer is 1.
