The probabilities from the venn diagram are:
Let A be the event that the Mechanic is AC repairman and T be the event that he does tune ups.
![P(A\cap T)=(2)/(13)](https://img.qammunity.org/2023/formulas/mathematics/high-school/9ykv04ta6kkw8h3epyzask7q7s1udej1wn.png)
The probability that he does tune ups is:
![P(T)=(3)/(13)](https://img.qammunity.org/2023/formulas/mathematics/high-school/mvrrjri2pv4mrsgprnctnzmb1oe8rascc1.png)
Hence the required probability is given by:
![P(A|T)=(P(A\cap T))/(P(T))=((2)/(13))/((3)/(13))=(2)/(3)](https://img.qammunity.org/2023/formulas/mathematics/high-school/pxn5egl1d7868yh123l62v3q15thqysfco.png)
Hence the probability is 2/3.