Higher November 2023 Paper 3 Q16
16 Zia has to set a 4-digit security passcode on her phone.
Each digit of the passcode is a number from 1 to 9
She can use each number more than once.
Zia tells her friend Amber that
the first digit is a cube number
the second digit is a prime number
the third digit is greater than 6
the fourth digit is an odd number.
The diagram shows one possible 4-digit passcode.

Amber is going to have one attempt at guessing Zia’s passcode.
Work out the probability that Amber guesses Zia’s passcode on the first attempt. (3)
| Answer | Mark | Mark scheme |
|---|---|---|
| \(\dfrac{1}{120}\) | P1 | for correctly identifying at least two of the number of options, eg 2 options for 1st digit, 4 options for 2nd digit |
| P1 | for process to multiply the four numbers of options with at least three correct, eg \(2 \times 4 \times 3 \times 5\ (= 120)\) or for process to multiply 4 fractions with at least 3 correct \(\dfrac{1}{2} \times \dfrac{1}{4} \times \dfrac{1}{3} \times \dfrac{1}{5}\) oe | |
| A1 | for \(\dfrac{1}{120}\) oe |
Additional guidance
May be seen as part of a calculation
| Position of digit | Number of options |
|---|---|
| 1st | 2 |
| 2nd | 4 |
| 3rd | 3 |
| 4th | 5 |