A necklace is made by stringing N individual beads together in the repeating pattern red bead, green bead, white bead, blue bead and yellow bead. If the necklace begins with a red bead and ends with a white bead, then N could be:  Choose the correct choice from the following answers:
A) 38
B) 77
C) 68
D) 29
E) 112
The pattern is R G W B Y R G W B Y R .......   So, White bead comes at these positions 3rd, 8th, 13th, 18th...   If we take this as a arithmetic progression, then this series can be expressed as 3 + (n - 1) 5. ( From the formula for general term of AP = a + (n-1)d).   This can be expressed as 5n - 2   We check the answer options so only 68 satisfy the condition.   Answer:68
<result>C</result>
A necklace is made by stringing N individual beads together in the repeating pattern red bead, green bead, white bead, blue bead and yellow bead. If the necklace begins with a red bead and ends with a white bead, then N could be: