Question

When a coin is tossed in an experiment, the result is either a head or a tail. A head is given a point value of $1$ and a tail is given a point value of $-1$. If the sum of the point values after $50$ tosses is $14$, how many of the tosses must have resulted in heads?

• A. $14$
• B. $18$
• C. $32$
• D. $36$
• E. $39$

Answer 1

Answer: (C)

$32$

Totally there are $50$ tosses.

Let the number of tosses which resulted head be $x$.

Therefore the number of tosses which resulted tail is $50-x$.

We get $x\times 1+(50-x)\times (-1)=14$

$x-(50-x)=14$

$x-50+x=14$

$x=32$