xxx

• Jul 12th, 2005

 

total number is 901/ number starting with 7 is 100/number ending with 7 is 90 number which has 7 in the middle is 90 = 280 so probability is 280/901

raghuram

• Jul 13th, 2005

 

14/45

raghuram

• Jul 13th, 2005

 

1/9 + 1/10 + 1/10 =28/90

raghuram

• Jul 13th, 2005

 

14/45

sarvesh kumar verma(IIITA)

• Aug 19th, 2005

 

280 numbers r having 7 out of total 900 numbers 
so probability is  
280/900=14/45

vineet srivastava

• Nov 30th, 2005

 

total no from 100 to 999 inclusive of both are 900. Numbers starting with 7 are 100, numbers with 7 at end which does not contain 7 at the beginning is 80 and numbers with 7 in middle but with no 7 at start or end is 72 (we are excluding certain numbers coz they have already been counted)

hence probability is 252/900 (i.e. 7/25)

parv

• Jul 21st, 2006

 

its wrong cuz the no's are 900 n 280 r no's wid 7 so its280/900 or 28/90 wich can be easily done by 1/9+1/10+1/10