Answer:
2
Step-by-step explanation:
We are given that Total people=60
Number of people ranked vanilla last=[tex]\frac{3}{5}\times 60=36[/tex]
Number of people ranked vanilla before chocolate =[tex]\frac{1}{10}\times 60=6[/tex]
Number of people ranked vanilla before strawberry=[tex]\frac{1}{3}\times 60=20[/tex]
We have to find number of people ranked vanilla first.
Number of people ranked before vanilla first=Number of people ranked before both
Number of people ranked before both=number of people ranked before chocolate+number of people ranked before strawberry+number of people ranked before neither-number of people responded
Number of people ranked before both=36+6+20-60=2
Hence, the number of people ranked vanilla firs=2