Hello, acc100jt!

Five letters are chosen from the word SINGAPURA.

Find the probability that the letters chosen can be used to form the word SINGA.

is it: . ? . . . . Yes!ItIs it possible to solve this question without using combination (nCr)?ispossible, but it takes more work . . .

(1) We canlistthe 126 possible 5-letter samples

. . . and then count the number that contain S,I,N,G,A (there are two).

(2) We could work out the probability like this.

Find the probability of getting S-I-N-G-A (in that order).

Since the order is unimportant, the probability is: .