PSLE Letters B, R and K formed a patten as shown below.
B R B K B B R B K B B R B K B . . .
If there are 142 'B', what is the greatest possible number of letters in the pattern?
Number of letters in 1 set of B R B K B = 5
Number of letters 'B' in 1 set of B R B K B = 3
Number of sets of 3 'B' if there are 142 'B'
= 142 ÷ 3
= 47 r 1
If the remainder is 1, there is 1 'B' and the largest possible number of letters is the final incomplete set is 2. (B R)
If the remainder is 2, there are 2 'B' and the largest possible number of letters is the final incomplete set is 4. (B R B K)
Greatest possible number of letters
= 47 x 5 + 2
= 235 + 2
= 237
Answer(s): 237