Call Me, Maybe?

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Three Englishmen and three Frenchmen work for the same company. Each of them knows a secret not known to others. They need to exchange these secrets over person-to-person phone calls so that eventually each person knows all six secrets. None of the Frenchmen knows English, and only one Englishman knows French. What is the minimum number of phone calls needed for the above purpose?

10 9 5 15

3 solutions

Naimish Khara
Mar 3, 2014

all have to call the person who knows English and French so there are 5 calls.. now when 5th person calls him then already he knows all secrets so hi will say to him secrets in that call and again call all other 4 persons to tell them secrets so total 5+4= 9 calls minimum required

The first and second statements are not necessarily true.

For example, if A is the Englishman who knows French, B and C are the other English man, we could have C call B, and then B calls A, and as it comes back, for A to call B and B to call C. In this construction, C never talks to A directly.

Calvin Lin Staff - 7 years, 3 months ago

Hafiz Khawar
Mar 22, 2014

i dont no

Dharishaanth Siva Shanmugam
Mar 4, 2014

Lets denote Englishmen as A, B and C. Whereas French men X, Y and Z.

Y and Z make a call. X and Y make a call. *X and Y knows all French men secrets.

B calls C. A and B make a call. *A and B knows all Englishmen secrets.

A, who speaks French make a call to X. *Now both know all ^ secrets.

A calls B again. B knows all secret. B calls C again. * to tell Frenchmen secret.

X calls Y again. *to tell Englishmen secrets. Y calls Z again.

9 calls altogether.

Call Me, Maybe?

3 solutions

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