Forty per cent of total number of students in a class got 80% or more than 80% marks. three-fourths of the remaining students got marks between 60% and 79% and the remaining students got less than 60% but above 50%. if the number of students securing less than 60% marks is 18, then the total number of students in the class is
Answers
Answered by
2
Let the the total no. of students be x
Therefore student getting 80% or above= 40/100 × x
=2x/ 5
Remaing no. of students= x - 2x/5
= 3x/5
No. of student getting between 60 and 79 = 3/4 of 3x/5
= 9x/ 20
Therefore total no. of student getting above 60% = 2x/ 5 + 9x/20
=17x/20
According to the problem,
x - 17x/20 = 18
=> 3x/20 = 18
=> x = (18×20)/3 = 120
Therefore total no. of student is 120
Therefore student getting 80% or above= 40/100 × x
=2x/ 5
Remaing no. of students= x - 2x/5
= 3x/5
No. of student getting between 60 and 79 = 3/4 of 3x/5
= 9x/ 20
Therefore total no. of student getting above 60% = 2x/ 5 + 9x/20
=17x/20
According to the problem,
x - 17x/20 = 18
=> 3x/20 = 18
=> x = (18×20)/3 = 120
Therefore total no. of student is 120
Similar questions