Three unbiased coins are tossed. What is the probability of getting at most 2 tails ?

Engineering

Mathematics

Basic Definitions Related to Probability

Question

Three unbiased coins are tossed. What is the probability of getting at most 2 tails ?

A

$\frac{1}{2}$

B

$\frac{5}{8}$

C

$\frac{7}{8}$

D

$\frac{1}{4}$

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Possible outcomes of tossing three coins are :

(HHH), (HHT), (HTH), (THH), (TTT), (TTH), (THT), (HTT)
where, H and T are represent "heads" and "tail".
Total no. of outcomes = 8
No. of outcomes with at the most two tails = 7

∴ Required probability $= \frac{7}{8}$

∴ Option C is correct.