Answer:
P = 7.14%
The percentage of those 30 years or older that own an ipod is 7.14%
Step-by-step explanation:
Given;
Percentage of ipod owners Pi = 20%
Percentage who don't own ipod Pd = 100-20 = 80%
For age 30 or older;
Percentage of ipod owners who belong to this group
Po = 20% of Pi
Percentage who don't have an ipod but belong to this group Pu = 100-35% = 65% of Pd
The percentage of those 30 years or older that own an ipod is;
P = Po/(Po+Pu) × 100%
Po = 20% of Pi = 20% of 20% = 0.2×20 =4%
Pu = 65% of Pd = 65% of 80% = 0.65×80% = 52%
Substituting the values;
P = 4/(4+52) × 100%
P = 7.14%