Total customers are = 360
Number of polled people who purchased ice cream = 260
Number of polled people who purchased both ice cream and yogurt = 250
Hence, people who purchased only ice cream are=[tex]260-250=10[/tex]
And [tex]360-10=350[/tex] are people who purchased yogurt.
So, people who purchased yogurt only = [tex]360-(250+10)=100[/tex]