funny calculations

Hi


There are 4 people named a,b,c,d.They are on a bank of a river. They need to cross the river using a bridge. It is very dark and they will have to cross with a help of a torch. nOW THE CONDITIONS

The torch will last for only 17 minutes.
a will cross in 1 minute
b will cross in 2 minute
c will cross in 8minutes
d will cross in 10 minutes

Only 2 people should go together.
one person should come back to the starting position.

The ? is what is the combination of persons

i think a and c will go together, as one person should return to starting point, a will take 16 min

hi suja


ALL PERSONS SHOULD CROSS THE BRIDGE.WE WILL HAVE TO FIND OUT ALL THE COMBINATIONS
yOURS
AKALYA

Originally Posted by akalyaraju

Hi


There are 4 people named a,b,c,d.They are on a bank of a river. They need to cross the river using a bridge. It is very dark and they will have to cross with a help of a torch. nOW THE CONDITIONS

The torch will last for only 17 minutes.
a will cross in 1 minute
b will cross in 2 minute
c will cross in 8minutes
d will cross in 10 minutes

Only 2 people should go together.
one person should come back to the starting position.

The ? is what is the combination of persons

Hi akalyaraju,
The answer is:
First 'a' & 'b' will go together with the torch
1 & 2 = 2 min (max time)

then 'b' will return back with torch
2 + 2 (earlier 2 min used) = 4 min

then 'c' & 'd' will go torch
8 & 10 = 10 min (max time)
10 + 4 (earlier 4 min used) = 14 min

now 'a' will return with torch
1 + 14 (earlier 14 min used) = 15 min

now 'b' will go back with torch (leaving 'a' behind)
2 + 15(earlier 15 min used) = 17 min (Answer)

so 'b', 'c' & 'd' will be on the other side
and 'a' this side

Am I right?

Diana

Hi Diana

You are absolutely right. Only the last combination is AB. because the condition is everyone shd cross in the end. How long did you take to do this? i couldn't do this. ONLY my husband solved this. Bye

Yours
Akalya

Hi,

How can last be AB. You said only one should be in the starting position. A & B start the game and end the game, leaving only A at the starting place.

I did this in 15 min. as i knew one similar to this.

let me put down:

There are 4 people on one side of the river.

A - father weighing 50Kg
B - mother weight 50 kg
C - son weighing 25 kg
D - daughther weighing 25 kg

then can cross the river using a boat. But the boat can carry weight only 50 kg maximum. They have to use the boat themselves (no other person to row). Now tell me how will all reach the other end.

All the best

Diana

Hi Diana...

C & D first cross and D remains there

C returns in the boat

A crosses and D comes back with the boat

C and D again go and d remains there

C returns again.

B crosses the boat and D returns

C and d then again go together

Originally Posted by diana

Hi,

How can last be AB. You said only one should be in the starting position. A & B start the game and end the game, leaving only A at the starting place.

I did this in 15 min. as i knew one similar to this.

let me put down:

There are 4 people on one side of the river.

A - father weighing 50Kg
B - mother weight 50 kg
C - son weighing 25 kg
D - daughther weighing 25 kg

then can cross the river using a boat. But the boat can carry weight only 50 kg maximum. They have to use the boat themselves (no other person to row). Now tell me how will all reach the other end.

All the best

Diana

Absolutely right

Diana

Hi diana,

where r u in salmiya. # yrs baack I was in Kuwait for a year. I stayed in the Caesar's takeway building , near ICSK.

Originally Posted by diana

Absolutely right

Diana

Hi saraswathi,

I stay near the Indian community school salmiya.

Diana