Problem Solving (PS) | A class has 150 students numbered from 1 to 150. All even numbered stu

Closest multiple of LCM(2,5,7) to 150 is 140

Number of co-primes of 2, 5 or 7 from 1 to 140 =\(140(1-\frac{1}{2})*(1-\frac{1}{5} ) *(1-\frac{1}{7}) =48\)

Number of co-primes of 2, 5 or 7 from 141 to 150= 3 {141,143 and 149}

Number of the students are in none of these clubs =51


OR


Number of students in the Math club =[150/2] = 75

Number of students in the Physics club =[150/5] = 30

Number of students in the Astronomy club =[150/7] = 21

Number of students in the Math club and Physics club =[150/10] = 15

Number of students in
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