Counterfeit coin

In 80 coins 1 coin is counterfeit which is minimum no. Of weighings to find out counterfeit coin.

Answered by: santhakumar.mit on: Aug 27th, 2010

80 coins divided as 27 27 and 26 coins..

then 27 is divided as 9 9 9 or 26 is divided as 9 9 8

then 9 is divided as 3 3 3 or 8 as 3 3 2 and

finally 3 as 1 1 1 or 2 as 1 1

so finally minimum number of weighing required 4

This one is correct one

Answered by: aniket.par on: Dec 20th, 2009

80 coins divided as 27,27 and 26 coins..

then 27 is divided as 9,9,9 or 26 is divided as 9,9,8
then 9 is divided as 3,3,3 or 8 as 3,3,2
and finally 3 as 1,1,1 or 2 as 1,1

so finally minimum number of weighing required= 4

A man ate 100 bananas in five days, each day eating 6 more than the previous day. How many bananas did he eat on the first day?

Member Since Feb-2008 | Answered On : Feb 9th, 2008

x+(x+6)+(x+12)+(x+18)+(x+24)=100
or, x=8

Answered by: prititripathi on: Feb 25th, 2011

x+x+6+x+12+x+18+x+24=100

on solving we get x=8
first day he ate 8 banana

Answered by: shiva074 on: Jun 18th, 2010

at first day he eats 8 bananas, then 14,20,26,32

In 80 coins one coin is counterfiet what is minimum number of weighings to find out counterfiet coin?

View all answers by Himanshu Ashwani

Member Since Oct-2008 | Answered On : Oct 16th, 2008

Divide Coins As 27 27 26
now weigh 27 and 27 keeping on both sides of pan u will get the less one
and if both sides are equal then group that has 26 coins has the coin that is counterfiet...
if u get 27 as result divide it in 3 groups
9 9 9
and weight it
keep two groups on two sides of pans and get the result of both sides are equal then the group 9 which was not kept on the pan has the coin which is counterfiet....
now 9 is divided as in 3 groups as
3 3 3 and weigh again and get result
now divide 3 as
1 1 1 and get the coin..
in start if u get answer as 26 divide as 3 groups
9 9 8
wiegh by keeping 9 on both sides and get answer if both are equal then 8 is ans
if 9 is ans again divide as 3 3 3 and then 1 1 1 and get coin...
if u get 8 then divide as 2 2 2 then 1 1 less one be yours coin...

Answered by: Aarthyanbu on: Dec 10th, 2009

It is about 5 times... First step to split those 80 coins into 40. then again split 40 to 20. divide 20 into 10 and then 5 finally 2 at last find the minimum weight...

Answered by: Himanshu Ashwani on: Oct 16th, 2008

The answer is 4Divide Coins As 27 27 26now weigh 27 and 27 keeping on both sides of pan u will get the less oneand if both sides are equal then group that has 26 coins has the coin that is counte...

Tcs quantitative aptitude questions

1. My flight takes of at 2am from a place at 18n 10e and landed 10 hrs later at a place with coordinates 36n70w. What is the local time when my plane landed.A) 6:00 am b) 6:40am c)7:40 d)7:00 e)8:00 2.In 80 coins one coin is counterfiet what is minimum number of weighings to find out counterfiet coin...

Answered by: Murugesan_s on: Jan 27th, 2010

If it is east to west we should add the degrees and convert that to min. then should subtract with the total hrs given. If it is west to east do it inverse manner.

In this problem 70+10=80;80*4 min=320 min=5 hr 20 min
then total hrs given=10 hrs=>10 hr-5 hr 20 min=6 hr 40 min

Answered by: avin2v2 on: Jul 23rd, 2008

3 since in 2 coins only 1 weighing is required 3 also 1 if 2 coins r identical then third coin is defective or else one of the 2 is defective 4,5,6,7,8 needs 1 test 9 requires 2 tests 27 requires...