jjack0310 wrote:
Bunuel wrote:
9. Julie is putting M marbles in a row in a repeating pattern: blue, white, red, green, black, yellow, pink. If the row begins with blue marble and ends with red marble, then which of the following could be the value of M?
A. 22
B. 30
C. 38
D. 46
E. 54
There are total of 7 different color marbles in a pattern. Now, as the row begins with blue marble and ends with red marble (so ends with 3rd marble in a pattern) then M=7k+3. The only answer choice which is multiple of 7 plus 3 is 38=35+3.
Answer: C.
Sorry, this may be a silly thing to ask, I don't understand the problem.
What exactly is it asking?
Can someone please explain?
I get that it is asking how many marbles does Julie have. Here is what I am understanding:
Basically there are marbles with seven different colors. Out of which blue, white and red always stay in that order since these three form a pattern. The rest of the four marbles of different colors can be in any order. But the 8th marble will always be blue followed by white and followed by white.
Is this thinking/approach correct??
If yes, where does 38 come from and if it is not correct, please tell me what's wrong.
Thanks
No, that's not correct.
The question asks to determine how many marbles Julie has.
The pattern is always the same {blue, white, red, green, black, yellow, pink}{blue, white, red, green, black, yellow, pink}{blue, white, red, green, black, yellow, pink}...
At some point Julie does not have enough marbles to end the pattern and the row ends with a red marble: {blue, white, red}.
For example, it could happen if she had 7+3=10 marbles:
{blue, white, red, green, black, yellow, pink}{blue, white, red}
Or 7*2+3=17 marbles:
{blue, white, red, green, black, yellow, pink}{blue, white, red, green, black, yellow, pink}{blue, white, red}
Or: 7*3+3=24 marbles:
{blue, white, red, green, black, yellow, pink}{blue, white, red, green, black, yellow, pink}{blue, white, red, green, black, yellow, pink}{blue, white, red}
As you can see the number of marbles is always a multiple of 7 plus 3.
The only answer choice which is multiple of 7 plus 3 is 38 = 7*5+3:
{blue, white, red, green, black, yellow, pink}{blue, white, red, green, black, yellow, pink}{blue, white, red, green, black, yellow, pink}{blue, white, red, green, black, yellow, pink}{blue, white, red, green, black, yellow, pink}{blue, white, red}.
Hope it's clear.