The ratio of number of boys and girls in a class is 3 : 2. In the 1st semester exam 20% of boys and 25% of girls get more than or equal to 90% marks. What percentage of students get less than 90% marks ?
The ratio of number of boys and girls in a class is 3 : 2. In the 1st semester exam 20% of boys and 25%
of girls get more than or equal to 90% marks. What percentage of students get less than 90% marks ?
a) 56 b) 70 c) 78 d) 80
. Expl : Let boys =3x and girls =2x.
Number of those who get less than 90% mark =(80% of 3x) + (75% of 2x)
=(80/100 )*3x +(75/100 *2x) =39x/10
Required percentage = (39x/10 *1/5x *100)% = 78%.
of girls get more than or equal to 90% marks. What percentage of students get less than 90% marks ?
a) 56 b) 70 c) 78 d) 80
. Expl : Let boys =3x and girls =2x.
Number of those who get less than 90% mark =(80% of 3x) + (75% of 2x)
=(80/100 )*3x +(75/100 *2x) =39x/10
Required percentage = (39x/10 *1/5x *100)% = 78%.
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