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Question

Mathematics Question on permutations and combinations

Number of ways of forming a committee of 66 members out of 55 Indians, 55 Americans and 55 Australians such that there will be atleast one member from each country in the committee is

A

3375

B

4375

C

3875

D

4250

Answer

4375

Explanation

Solution

Required cases are as follow: \therefore Required number of committee =5C1×5C1×5C4+5C1×5C2×5C3+5C1×5C3={ }^{5} C_{1} \times{ }^{5} C_{1} \times{ }^{5} C_{4}+{ }^{5} C_{1} \times{ }^{5} C_{2} \times{ }^{5} C_{3}+{ }^{5} C_{1} \times{ }^{5} C_{3} ×5C2\times{ }^{5} C_{2} +5C1×5C4×5C1+5C2×5C1×5C3+5C2×5C2+{ }^{5} C_{1} \times{ }^{5} C_{4} \times{ }^{5} C_{1}+{ }^{5} C_{2} \times{ }^{5} C_{1} \times{ }^{5} C_{3}+{ }^{5} C_{2} \times{ }^{5} C_{2} ×5C2+5C2×5C3×5C1+5C3×5C1×5C2+5C3\times{ }^{5} C_{2}+{ }^{5} C_{2} \times{ }^{5} C_{3} \times{ }^{5} C_{1}+{ }^{5} C_{3} \times{ }^{5} C_{1} \times{ }^{5} C_{2}+{ }^{5} C_{3} ×5C2×5C1+5C4×5C1×5C1\times{ }^{5} C_{2} \times{ }^{5} C_{1}+{ }^{5} C_{4} \times{ }^{5} C_{1} \times{ }^{5} C_{1} =5×5×5+5×10×10+5×10×10+5×5×5= 5 \times 5 \times 5+5 \times 10 \times 10+5 \times 10 \times 10+5 \times 5 \times 5 +10×5×10+10×10×10+10×10×5+10×5+10 \times 5 \times 10+10 \times 10 \times 10+10 \times 10 \times 5+10 \times 5 ×10+10×10×5+5×5×5\times 10+10 \times 10 \times 5+5 \times 5 \times 5 =125+500+500+125+500+1000+500+500= 125+500+500+125+500+1000+500+500 +500+125+500+125 =4375= 4375