In a histogram, the classes 0<x≤50<x\leq50<x≤5, 5<x≤15 5<x\leq15\,5<x≤15 and 15<x≤25 15<x\leq25\,15<x≤25 have frequency densities 6, k k\,k and 2 respectively. The total frequency is 90, and 50 observations lie in the first two classes.
Find kkk.
Determine whether the stated total frequency is consistent with the other information.
278 exam-style questions on CCEA A Level Maths 2.5 Data presentation and interpretation, covering 2.5.1 Data presentation and interpretation, 2.5.2 Data presentation and interpretation, 2.5.3 Data presentation and interpretation, 2.5.4 Data presentation and interpretation, 2.5.5 Data presentation and interpretation, 2.5.6 Data presentation and interpretation, 2.5.7 Data presentation and interpretation, 2.5.8 Data presentation and interpretation, 2.5.9 Data presentation and interpretation, and 2.5 Data presentation and interpretation. Each one has a worked solution and a mark scheme showing where the marks go.