PS - Strings

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

Please give explaination to the answer.

TStokes · Answer

My answer is E) 68

I just played with the numbers to get this answer. I would be interested in a formula that is easier though.

ALD · Answer

is the answer D-68. i don't think there is a way of solving this. you have to check every answer.

there are 5 different color of beads , so 13 times these beads can be repeated in order. that gives 13*5=65, the remaining 3 will be red, green and the last will be white bead.

hope i have explained it well.

sprtng · Answer

68 for me as well.

pattern is 5 beads long, if it starts on red and ends on white, then it must be 5x+3 so if x is odd then we have a 8, even, then we have a 3....68 is the only matching choice

pn · Answer

sprtgn: Can you explain in detail how it is 5x+3

OA: E) 68

mendelay · Answer

E.

The answer must be a number that ends in 3 or 8.

sprtng · Answer

because it says that "If the necklace design begins with a red bead and ends with a white bead" red is the first bead in the pattern, and white is the third bead.

(for short, red bead (r), green bead(g), white bead(w), blue bead(b), and yellow bead(y)
so for example, the design could be: r g w b y r g w = starts with red, ends with white, in this design, it has completed the pattern (r ~ y) once, which contains 5 beads, then the extra unfinished pattern which starts with read ends with w gives us 3.

so lets say...the design could be the pattern repeated 6 times ( 30 beads) before it stopped, because the design can't stop on a yellow, which is the last of the pattern, then it has to go on until it reaches white, which is that extra 3 beads, then we have 5*6 + 3...and so forth....which gives us 5 * x (however many times the pattern has repeated, could also be zero), and that extra 3 bead in order to get to white bead (read, green, white) to finish the design off. ... a little messy, let me know if it's still unclear!

pn · Answer

Thanks sprtng, its clear now :-D

Thanks Everyone

ajayvarmasv · Answer

E

68 is the only multiple of 5 +3

PS - Strings

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