In: Advanced Math
A rock group needs to choose 3 songs to play at the annual Battle of the Bands. How many ways can they choose their set if have 15 songs to pick from?
A rock group has to choose 3 songs out of 15 songs to play at the annual battle of the bands.
The number of ways in which the rock group can pick 3 songs from 15 songs will be equal to the number of combinations of 15 objects taking 3 at a time.
Use the general formula of combinations,
C(n, r) = n!/r!(n – r)! ...... (1)
Substitute n = 15 and r = 3 in (1) and simplify,
C(15, 3) = 15!/3!(15 – 3)!
= (15 × 14 × 13 × 12!)/(3 × 2 × 1) × 12!
= 455
Therefore, the rock group can pick 3 songs from 15 songs in 455 ways.
Therefore, the rock group can pick 3 songs from 15 songs in 455 ways.