There are 20 coins placed on a table such that tails is showing up. Suddenly electricity goes off and a boy sitting nearby inverts few coins and then he asks another boy to select some coins such that number of inverted coins is equal in every other subpart. He selects 8 coins and invert those 8 coins , and when electricity comes back he sees equal number of inverted coins in both subparts. Tell how many coins did first boy inverted.

P.S. The question is not original.

No vote yet

1 vote

×

Problem Loading...

Note Loading...

Set Loading...

Easy Math Editor

`*italics*`

or`_italics_`

italics`**bold**`

or`__bold__`

boldNote: you must add a full line of space before and after lists for them to show up correctlyparagraph 1

paragraph 2

`[example link](https://brilliant.org)`

`> This is a quote`

Remember to wrap math in \( ... \) or \[ ... \] to ensure proper formatting.`2 \times 3`

`2^{34}`

`a_{i-1}`

`\frac{2}{3}`

`\sqrt{2}`

`\sum_{i=1}^3`

`\sin \theta`

`\boxed{123}`

## Comments

Sort by:

TopNewestIf you assume n coins to be inverted in both, then first would have inverted his n and others 8-n. So he inverted 8 in total

Log in to reply

Its answer is 8

Log in to reply

Sounds like a potentially good puzzler. Although, what a

subpartis, isn't clear.Log in to reply

The problem is given in a technothlon problem . I am also confused with the term subparts. But it sounds like two groups from the phrase "equal number of inverted coins in both subparts". The options were given as 5 , 8 , 10 , 12. Now you can try.......

Log in to reply

What is a technothlon?

Log in to reply

Log in to reply

Log in to reply

Log in to reply

Log in to reply

Probably 10

Log in to reply

Read my answer. Its 8

Log in to reply