Question

in a school 50% of the students are younger than 10, 1/20 are 10 years old and 1/10 are older than 10 but younger than 12, the remaining 70 students are 12 years or older. how many students are 10 years old?

Answer 1

let us keep total number of students as x  50%of students as x%2 and the remaining 50%as x%2  x%2=1%10+1%20+70=1403students total students =x%2+x%2=1403+1403=2806 no of students 10 years old =1%20 of 2806=1403 students are 10 years old