Question 1113783: 1/8 part of a pencil is blck and 1/2 part of the remaining is white. If the remaining part is blue and length of this blue part is 3 1/2 cm. then find the length of the pencil.
a)6cm
B)7cm
C)8cm
D)9cm
Found 4 solutions by stanbon, KMST, rothauserc, amalm06:
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! 1/8 part of a pencil is blck and 1/2 part of the remaining is white. If the remaining part is blue and length of this blue part is 3 1/2 cm. then find the length of the pencil.
Let the length be "x"::
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white = (1/2)(7/8)x = 7/2 cm
(7/8)x = 7
x = 8 cm
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Cheers,
Stan H.
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a)6cm
B)7cm
C)8cm
D)9cm
Answer by KMST(5328)  (Show Source):
You can put this solution on YOUR website! DIVIDE AND CONQUER FOR UNDERSTANDING:
 of the pencil is black.
The remaining is  of the pencil.
Half of "the remaining" is  of the pencil.
That  of the pencil is white.
As a fraction of the pencil, the black part and the white part amount to
 .
The rest of the pencil is blue.
As a fraction of the pencil the blue part is
 .
So, if  = the length of the pencil, in cm,
and the length of blue part, in cm, is  ,
our equation is
 .
JUST EQUATIONS:
If you wanted to write the whole thing as an equation in one step,
with no words for explanation, you could write
.
SOLVING THE SIMPLIFIED FINAL EQUATION:
 (optional intermediate step)
So the length of the whole pencil is  .
CHEAT:
Looking at the multiple choice answers can help.
If you thought about working backwards from the multiple choice answers,
8cm looks like a winner.
Checking it out, you see that it would give you a 1-cm black part,
leaving 7 cm to be split half and half between the white and blue parts,
making the length of each  cm.
Answer by rothauserc(4718)  (Show Source):
You can put this solution on YOUR website! (1/8) is black + (1/2)(7/8) is white + (7/16) is blue
:
(7/16) * x = 3.5 cm
:
7x = 56
:
x = 8
:
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answer is C, 8 cm
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:
Answer by amalm06(224)  (Show Source):
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