(a) Lynda spins the spinner shown below - Junior Cycle Mathematics - Question 4 - 2017

To estimate the number of times Lynda's spinner would land on grey when spun 60 times, we calculate the proportion of the grey sector:

The angle for grey is 90°, and we have a total of 360° in the spinner:

$P(Grey) = \frac{90}{360} = \frac{1}{4}$

Now, to find out how many times we can expect it to land on grey:

$Expected \ Count = P(Grey) \times 60 = \frac{90}{360} \times 60 = 15$

So, we would expect it to land on grey approximately 15 times.

To complete the table for the probabilities of events A, B, C, and D, we need to calculate the missing values:

• For Event B:

  • Fraction: Since B accounts for half of the total probability, it is $\frac{1}{2}$.
  • Percentage: 50%.
  • Decimal: 0.5.

• For Event D:

  • Fraction: D represents 2%, which is $\frac{1}{50}$ when expressed as a fraction.
  • Decimal: 0.02.

So, the completed table looks like this:

Event	Fraction	Percentage	Decimal
A	1/4	25%	0.25
B	1/2	50%	0.50
C	2/5	40%	0.40
D	1/50	2%	0.02

The probabilities of events A, B, C, and D can be marked on a scale ranging from 0 to 1 as follows:

• A: 0.25
• B: 0.50
• C: 0.40
• D: 0.02

The scale would look something like this when the points are marked:

0    0.1   0.2   0.3   0.4   0.5   0.6   0.7   0.8   0.9   1
            |            |  |  |             |
            A            C  B             D

Each event is represented at its corresponding probability on the scale.