Question

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 design begins with a red bead and ends with a white bead, then N could equal

A. 16
B. 32
C. 41
D. 54
E. 68

Answer 1

totally 5 beads are repeated. If N times repetitions considered total 5N beads are required. As the necklace ends with white one and it is 3rd bead in the repetition order, assume 5N+3 beads are required.
That means if we subtract 3 from the required ,we get 5N beads.
then it is a multiple of 5.from the given options only 65 satisfies the condition.
68-3=65,which is a multiple of 5.So the ans is E.

Answer 2

The bead patterns repeats after every fifth bed.
Since the first bead in this design is red and the last bead in this design is white,the number of beads in the design is 3 more than some multiple of 5.
this can be expressed as 5n+3,where n is an integer.
Test each of the answer choices to determine which is multiple of 5 plus a value of 3.Of the options ,only 68=5(13)+3 can be written in the form 5n+3.
So,the answer is 68.
The option is E