(a) A doctor treated 2,000 patients over a period of time. If he worked for 5 hours a day and spent 15 minutes on each patient, how many days did the doctor spend to treat all the patients?

(b) The pie chart shows the distribution of textbooks to six classes A, B, C, D, E and F in a school.
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(i) If Class D was given 720 textbooks, how many textbooks were distributed to each of the remaining classes?
(ii) What is the average number of textbooks distributed to the classes?
(iii) How many classes had less than the average number of textbooks distributed?