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Let x denotes the number of heads in a simultaneous toss of three coins, then P(0<x3)P(0 < x \leq 3)

Solution

Correct Option: 3

When tossing 3 coins simultaneously, let xx denote the number of heads obtained.

The condition 0<x30 < x \leq 3 means xx can be 1, 2, or 3 (at least one head).


When tossing 3 coins, each coin shows either H (Head) or T (Tail).

Total possible outcomes =2×2×2=8= 2 \times 2 \times 2 = 8

All possible outcomes:

OutcomeNumber of Heads (x)
HHH3
HHT2
HTH2
HTT1
THH2
THT1
TTH1
TTT0

Outcomes where 0<x30 < x \leq 3 (i.e., x=1,2,x = 1, 2, or 33):

x=1x = 1: HTT, THT, TTH → 3 outcomes

x=2x = 2: HHT, HTH, THH → 3 outcomes

x=3x = 3: HHH → 1 outcome

Favorable outcomes =3+3+1=7= 3 + 3 + 1 = 7

Alternatively, only TTT has 0 heads, so favorable outcomes =81=7= 8 - 1 = 7


P(0<x3)=Favorable outcomesTotal outcomesP(0 < x \leq 3) = \dfrac{\text{Favorable outcomes}}{\text{Total outcomes}}

P(0<x3)=78P(0 < x \leq 3) = \dfrac{7}{8}

Therefore, the probability is 78\dfrac{7}{8}.

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