ix identical coins are arranged in a row. The number of ways in which the number of tails is equal to the number of heads is20912040

Three coins were tossed simultaneously. Each time the number of heads occurs is noted in the given data. Find the number of times only tails occurred.

John throws 150 coins onto a table. 60 of them show „head“, the others show „tail“. He wants the same amountof coins to show „head“ as „tail“. How many coins that show „head“ does he have to turn over?(A) 10 (B) 15 (C) 20 (D) 25 (E) 30

How would you distinguish one non-identical coin from a pile of nine coins where eight are identical?

A sequence of terms, a1, a2, a3, …….. ai, is generated as follows. The first term (a1) is chosen as 1. To obtain every subsequent term a coin is tossed. If a heads (H) appears, the next term is obtained by adding 2 to the previous term. If a tails (T) appears, only 1 is added to the previous term to obtain the next term. For example, the sequence corresponding to HTH is 1, 3, 4, 6. If a11 = 15, what is the maximum number of consecutive tails that could have appeared up to that term?

Yet Another Coin Problem