In the following question, two statements are numbered as Statement I and II. On solving these statements we get Quantity A and B respectively. Solve the given statements for the both quantities and choose the correct option. Statement I: In a class of 28 boys and 12 girls, a group of 5 boys and 3 girls is to be sent to represent the class in an exhibition. In how many ways can the teacher select the students? Statement II: In a class of 40 students, 1/4 of which are girls, has to take a group of 12 students on an expedition to Nainital. If there must be at least 3 girls in the group, then find the number of ways in which the selection can be done.
In the following question, two statements are numbered as Statement I and II. On solving these statements we get Quantity A and B respectively. Solve the given statements for the both quantities and choose the correct option. Statement I: In a class of 28 boys and 12 girls, a group of 5 boys and 3 girls is to be sent to represent the class in an exhibition. In how many ways can the teacher select the students? Statement II: In a class of 40 students, 1/4 of which are girls, has to take a group of 12 students on an expedition to Nainital. If there must be at least 3 girls in the group, then find the number of ways in which the selection can be done. Correct Answer Quantity A < Quantity B
Statement I:
Total no. of boys = 28
⇒ No. of ways of selecting 5 boys = 28C5 = 28!/(5! × 23!) = 98280
Total no. of girls = 12
⇒ No. of ways of selecting 3 girls = 12C3 = 12!/(3! × 9!) = 220
∴ Total no. of ways of selection = 98280 × 220 = 21621600
∴ Quantity A = 21621600
Statement II:
Total no. of students = 40
⇒ No. of girls = 40 × 1/4 = 10
⇒ No. of boys = 40 – 10 = 30
Since the group must have 3 girls,
⇒ No. of ways of selecting 3 girls = 10C3 = 10!/(3! × 7!) = 120
⇒ No. of students left in the class = 40 – 3 = 37
⇒ No. of ways of selecting other 9 students = 37C9 = 37!/(9! × 28!) = 124403620
∴ Total no. of ways of selections = 124403620 + 120 = 124403740
∴ Quantity B = 124403740
∵ 21621600 < 124403740
∴ Quantity A ˂ Quantity B