The cumulative frequency diagram shows the times taken by the members of two different clubs, The Braineys and The Cleverites, to complete an intelligence test.
Cumulative
frequency
a) Find the median and the
interquartile range for The Cleverites
80
60
b) State which club, on average, was
slowest at completing the test.
Give a reason for your answer.
40
The Cleverites
The Braineys
20
0
10
20
50
30
40
Time, in minutes​

the system of inequity is

step-by-step explanation:

from the given graph it is noticed that we have two related lines. one is solid and another is dashed.

if a line passing through two points, then the equation of line is

the solid line passing through the points (0,4) and (4,0).

the related equation of solid line is .

similarly, find the related equation of dashed line. the dashed liune passing through the points (0,0) and (3,1).

the related equation of dashed line is

from the given graph it is noticed that the point (0,1) lies on the shaded region, therefore the point (0,1) must be satisfied by the related equations.

check the related equations by the point (0,1).

this statement is true if the sign of inequality is < instead of equality. since it is an solid line therefore the sign of inequality will be . the required inequality is

similarly, check the second related equation.

it is a dashed line, so this statement is true if the sign of inequality is > . the required inequality is