We read your photo as:

If the probability of obtaining H was 0.2, find: i) The total number of times the die was thrown. ii) The probability of obtaining at least H

Mathematics

ScanSolve AI Answer

Answers

2 parts
i
210
ii

44105\frac{44}{105}

Step-by-step solution

5 steps

Here's the solution to the probability problem.

First, let's list the given frequencies from the table:

  • Frequency of 1: 33
  • Frequency of 2: 40
  • Frequency of 3: 49
  • Frequency of 4: xx
  • Frequency of 5: 42
  • Frequency of 6: 37

The problem states: "If the probability of obtaining H was 0.2". Given the context of a die roll, 'H' is likely a typographical error for one of the numerical outcomes. We need to find which outcome, when its probability is set to 0.2, results in integer values for the unknown frequency xx and the total number of throws.

Let NN be the total number of times the die was thrown.
The sum of all frequencies is N=33+40+49+x+42+37=201+xN = 33 + 40 + 49 + x + 42 + 37 = 201 + x.

We test the known frequencies:

  • If P(1)=0.2  ⟹  33N=0.2  ⟹  N=165P(1) = 0.2 \implies \frac{33}{N} = 0.2 \implies N = 165. Then x=165−201=−36x = 165 - 201 = -36 (invalid).
  • If P(2)=0.2  ⟹  40N=0.2  ⟹  N=200P(2) = 0.2 \implies \frac{40}{N} = 0.2 \implies N = 200. Then x=200−201=−1x = 200 - 201 = -1 (invalid).
  • If P(3)=0.2  ⟹  49N=0.2  ⟹  N=245P(3) = 0.2 \implies \frac{49}{N} = 0.2 \implies N = 245. Then x=245−201=44x = 245 - 201 = 44 (valid).
  • If P(5)=0.2  ⟹  42N=0.2  ⟹  N=210P(5) = 0.2 \implies \frac{42}{N} = 0.2 \implies N = 210. Then x=210−201=9x = 210 - 201 = 9 (valid).
  • If P(6)=0.2  ⟹  37N=0.2  ⟹  N=185P(6) = 0.2 \implies \frac{37}{N} = 0.2 \implies N = 185. Then x=185−201=−16x = 185 - 201 = -16 (invalid).

Both P(3)=0.2P(3)=0.2 and P(5)=0.2P(5)=0.2 lead to valid integer frequencies. Given the common occurrence of misinterpretations in handwritten text, we will proceed with the assumption that 'H' refers to the outcome '5', as it is a plausible misreading.

Assumption: The letter 'H' in the question "If the probability of obtaining H was 0.2" is a typographical error and refers to the outcome '5' from the die roll.

Part i· 2 steps

The total number of times the die was thrown.

  1. Use the given probability of obtaining 5 and its frequency to find the total number of throws.

    Given P(5)=0.2P(5) = 0.2 and Frequency of 5 = 42.
    The formula for probability is:

    P(outcome)=Frequency of outcomeTotal number of throwsP(\text{outcome}) = \frac{\text{Frequency of outcome}}{\text{Total number of throws}} 0.2=42N0.2 = \frac{42}{N} N=420.2N = \frac{42}{0.2} N=4202N = \frac{420}{2} N=210N = 210

    The total number of times the die was thrown is 210\boxed{210}.

  2. Calculate the value of xx (frequency of 4).

    The sum of all frequencies must equal the total number of throws, NN.

    N=Freq(1)+Freq(2)+Freq(3)+Freq(4)+Freq(5)+Freq(6)N = \text{Freq}(1) + \text{Freq}(2) + \text{Freq}(3) + \text{Freq}(4) + \text{Freq}(5) + \text{Freq}(6) 210=33+40+49+x+42+37210 = 33 + 40 + 49 + x + 42 + 37 210=201+x210 = 201 + x x=210−201x = 210 - 201 x=9x = 9

    So, the frequency of obtaining 4 is 9.

Part ii

44105\frac{44}{105}

The probability of obtaining at least 4.

  1. Identify the outcomes that are "at least 4" and sum their frequencies.

    "At least 4" means obtaining 4, 5, or 6.

    • Frequency of 4 (xx): 9
    • Frequency of 5: 42
    • Frequency of 6: 37 Number of outcomes "at least 4" = 9+42+37=889 + 42 + 37 = 88.
  2. Calculate the probability of obtaining at least 4.

    P(at least 4)=Number of outcomes "at least 4"Total number of throwsP(\text{at least 4}) = \frac{\text{Number of outcomes "at least 4"}}{\text{Total number of throws}} P(at least 4)=88210P(\text{at least 4}) = \frac{88}{210}
  3. Simplify the fraction.

    Both the numerator and the denominator are divisible by 2.

    P(at least 4)=88÷2210÷2P(\text{at least 4}) = \frac{88 \div 2}{210 \div 2} P(at least 4)=44105P(\text{at least 4}) = \frac{44}{105}

    The probability of obtaining at least 4 is 44105\boxed{\frac{44}{105}}.

Was this helpful?

Try one yourself

A new problem that tests the same skill.

Still stuck on this one?

Ask a follow-up, and the answer starts from this question.

Got a different question?Ask your own question