After a bride has interviewed 7 DJs to play at her wedding, her fiance tells her she needs to narrow it down to 4 DJs. In how many ways can she rank the 4 DJs

840

Step-by-step explanation:

Given

Required

Determine the number of rankings

The term "ranking" as used in this question implies permutation and the required is calculated using:

Where

So:

Hence, number of ranking is 840

8121 because

130,000 divided by 16 is 8121

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