Six teachers and 12 students volunteer for a committee to discuss extra-curricular activities. How many committees of 5 people can be made if: a) there must be exactly 3 students on the committee b) there must be at least one teacher and at least one student on the committee (3 marks)

Respuesta :

Answer:

a)[tex]X=3300[/tex]

b)[tex]Y=7770[/tex]

Step-by-step explanation:

From the question we are told that:

Number Teachers [tex]T=6[/tex]

Number Student [tex]S=12[/tex]

Number in committee [tex]n=5[/tex]

a) Generally the equation for exactly 3 students on the committee is mathematically given by

[tex]X=^{S}C_3*^{T}C_3[/tex]

[tex]X=^{12}C_3*^{6}C_3[/tex]

[tex]X=3300[/tex]

b) Generally the equation for at least one teacher and at least one student on the committee is mathematically given by

Total Ways-(no of ways of selection no teacher or student)

Where total Ways

[tex]T=^{(6+12)}C_5[/tex]

[tex]T=8568[/tex]

Therefore

[tex]Y=8568-^{6}C_0*^{12}C_5+^{12}C_0*^{6}C_5[/tex]

[tex]Y=8568-798[/tex]

[tex]Y=7770[/tex]