10 boys can dig apitch an 12 hours.How long will 8 boys take to do it?

THIS IS IN INVERSE PROPORTION:

=x₁y₁=x₂y_{2 .}

let time = x hours

=10 X 12 = 8 X x

=120 = 8x

=x=120/8

=x=15 hours.

OR BY UNITARY METHOD.

10 boys dig pitch in  = 12h

1  " " " "  = 12 X 10

8    " " " "  = 12  X 10/8

  =120/8

  =15 Hours.

HOPE IT REALLY HELPS YOU.

CHEERS!!!

DEEPAK JANGRA

  Let x be  the number of hours ,8 boys take to do the work

  So , 10 : 8 :: 12 : x

           Product of means = Product of extremes

          10x  = 12 * 8

           10x =  96

               x =  96 / 10

               x =  9.6

 Answer : 8 boys will take 9.6 hours to dig the pitch.

Hope u understood the concept,

Thumps up plz........

10 boys dig pitch in = 12h

1 " " " " = 12 X 10

8 " " " " = 12 X 10/8

=120/8

=15 Hours.

time taken for 10 boys to do it = 12 hrs.

10 boys take 12hrs. so 1 boy will take more time

1 boy = 10 x 12 = 120

So, 8 boys will take = 120/8 = 15 hrs

 guys why is propotion so confusing ?

I REVIEWED ALL THE ANSWERS. IF TEN BOYS TAKE 12 HRS. HOW CAN 8 BOYS TAKE 15 HRS. DID YOU MENTION THAT THESE BOYS WERE LAZY. IF THEY WERE, THE ANSWER IS CORRECT.

@david p john 

there is a solution for every problem 

hehhe

 10boy=12hrs

8boys=(12/10)*8=9.6hrs

if 10 boyz take 12 hrs

then 1 boy would take 1.2 hrs 

so 1.2 multiplied by 8 = 9.6 

result = therfore  8 boys would take 9.6 hrs 

hope so it would help :D