Higher June 2022 Paper 1 Q16
16 A first aid test has two parts, a theory test and a practical test.
The probability of passing the theory test is 0.75
The probability of passing only one of the two parts is 0.36
The two events are independent.
Work out the probability of passing the practical test. (4)
| Answer | Mark | Mark scheme |
|---|---|---|
| 0.78 | P1 | for using 0.75 or 0.25 in a relevant product, eg \(0.75 \times x\) or \(0.25 \times y\) |
| P1 | for using two products to form an equation, eg \(0.75x + 0.25y = 0.36\) | |
| P1 | for a correct equation in one variable, eg \(0.75(1 - p) + 0.25p = 0.36\) or \(0.75f + 0.25(1 - f) = 0.36\) | |
| A1 | oe |
Additional guidance
Allow different letters
Could work with fractions
Could set up an equation for
pass \(\times\) pass + fail \(\times\) fail = 0.64
Accept 78% or any equivalent fraction,
eg \(\dfrac{39}{50}, \dfrac{156}{200}\)