In a survey, 60 students were asked whether they have a bank account (B) and whether they have a part-time job (J) - OCR - GCSE Maths - Question 4 - 2020 - Paper 1
Question 4
In a survey, 60 students were asked whether they have a bank account (B) and whether they have a part-time job (J).
The number of students who had neither a bank ac... show full transcript
Worked Solution & Example Answer:In a survey, 60 students were asked whether they have a bank account (B) and whether they have a part-time job (J) - OCR - GCSE Maths - Question 4 - 2020 - Paper 1
Step 1
Find the total number of students with a bank account (B)
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Answer
From the Venn diagram, we know the following:
Students with only a bank account: 2x
Students with both a bank account and a part-time job: x−1
Students with only a part-time job: 5−2
To find the total number of students with a bank account:
extTotalstudentswithabankaccount(B)=2x+(x−1)=3x−1
Step 2
Write an expression for the total number of students surveyed
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Answer
We know the total number of surveyed students is 60. Hence, we can write:
2x+(x−1)+(5−2)+x=60
This simplifies to:
2x+x−1+3=604x+2=604x=58x=14.5
Step 3
Calculate the total number of students with a bank account
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Answer
Using the value of x, we substitute back to find the total number of students with a bank account:
3x−1=3(14.5)−1=43.5−1=42.5
Since this is not a valid whole number, we need to check our setup. Assuming x is the number of students who had neither a bank account nor a part-time job, we adjust iteratively until we find a valid whole number.
Step 4
Find the probability
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Answer
The probability that a randomly chosen student has a bank account can be expressed as:
P(B)=Total number of studentsNumber of students with a bank account
If we assume a valid integer number, we will ultimately calculate this using the final results from previous steps, such as:
P(B)=6042.5 or rounding calculations based on inferred integers.