The number of faults found on each of 70 cars is summarised in the table below, where a a\,a and b b\,b are positive integers.
| Number of faults | 0 | 1 | 2 | 3 | 4 |
|---|---|---|---|---|---|
| Frequency | 12 | aaa | 20 | bbb | 6 |
The mean number of faults per car is exactly 2.
Show that a+b=32a + b = 32a+b=32 and a+3b=76a + 3b = 76a+3b=76.
Find the value of a a\,a and the value of bbb.
Write down the mode of the number of faults.
105 exam-style questions on WJEC A Level Maths 2.2 Data presentation and interpretation, covering 2.2.1 Data presentation and interpretation, 2.2.2 Data presentation and interpretation, 2.2.3 Data presentation and interpretation, 2.2.4 Data presentation and interpretation, 2.2.5 Data presentation and interpretation, 2.2.6 Data presentation and interpretation, 2.2.7 Data presentation and interpretation, 2.2.8 Data presentation and interpretation, and 2.2 Data presentation and interpretation. Each one has a worked solution and a mark scheme showing where the marks go.