Question

Find the number of different signals that can be generated by arranging at least four

flags in order on a vertical staff, if five different flags are available.​

Answer 1

Answer:

a singal can have atleast two flags

ie ; singal can have 2flags, 3flags, 4flags or 5 flags too

we need to calculate seperately for each and then .

Step-by-step explanation:

FOR 2 FLAGS ; first 5 flags

second 4 flags

required no of signals = 5×4 =20

FOR 3 FLAGS ; first 5 flags

second 4 flags

third 3 flags

required no of signals = 5×4×3=60

FOR 4 FLAGS ; first 5 flags

second 4 flags

third 3 flags

fourth 2 flags

required no of signals = 5×4×3×2=120

FOR 5 FLAGS ; first 5 flags

second 4 flags

third 3 flags

fourth 2 flags

fifth1 flags

required no of signals =5×4×3×2×1= 120

flag types 2,3,4,5

no of signals 20,60,120,120

answer : therefore required signals = 320