PSLE Letters S, R and N formed a patten as shown below.
S R S N S S R S N S S R S N S . . .
If there are 133 'S', what is the greatest possible number of letters in the pattern?
Number of letters in 1 set of S R S N S = 5
Number of letters 'S' in 1 set of S R S N S = 3
Number of sets of 3 'S' if there are 133 'S'
= 133 ÷ 3
= 44 r 1
If the remainder is 1, there is 1 'S' and the largest possible number of letters is the final incomplete set is 2. (S R)
If the remainder is 2, there are 2 'S' and the largest possible number of letters is the final incomplete set is 4. (S R S N)
Greatest possible number of letters
= 44 x 5 + 2
= 220 + 2
= 222
Answer(s): 222