If 80% of the students in class score marks above 75 out of which 60% are girls. Find the probability that a student selected at random is a boy who has scored less than 75, given that percentage of boys in the class is 44.

Asked by renukanancyqueen2015 | 20th Dec, 2015, 07:56: PM

Expert Answer:

G i v e n space t h a t space p e r c e n t a g e space o f space b o y s space i n space t h e space c l a s s equals 44 percent sign T h u s comma space p e r c e n t a g e space o f space g i r l s space i n space t h e space c l a s s equals 56 percent sign G i v e n space t h a t space o u t space o f space 80 percent sign space o f space s t u d e n t s space 60 percent sign space a r e space g i r l s T h u s comma space 60 over 100 cross times 80 equals 48 space g i r l s. T h e r e f o r e space n u m b e r space o f space b o y s comma space w h o space g o t space a b o v e space 75 space m a r k s equals 80 minus 48 equals 32 N u m b e r space o f space b o y s comma space w h o space g o t less than 75 equals 44 minus 32 equals 12 S i m i l a r l y comma space t h e space n u m b e r space o f space g i r l s space w h o space g o t space less than 75 equals 56 minus 48 equals 8 T o t a l space n u m b e r space o f space s t u d e n t s equals 100 N u m b e r space o f space b o y s space w h o space g o t space less than 75 equals 12 T h e r e f o r e comma space t h e space p r o b a b i l i t y space t h a t space a space b o y space s c o r e d space l e s s space t h a n space 75 percent sign equals 12 over 100 equals 0.12

Answered by Vimala Ramamurthy | 21st Dec, 2015, 12:36: PM