Question

1/8 part of a pencil is black, 1/2 part of the remaining is white. If the remaining part is blue nd the length of this blue part is 3 1/2cm. Find the length of the pencil

Answer 1

simple solution of this question

suppose that total part of pencil is 1 part

1/8 = black

1 - 1/8 = 7/8 remaining

1/2 × 7/8 = white

7/16 is whit

remaining is blue is 7/2 cm

total length = 7/2 ÷ 7/16

= ( 7 × 16 ) ÷ ( 2 × 7 )

= 112/14 = 8 cm..

Answer 2

${\boxed {\orange {\bigstar{answer}}}}$

$\small \purple{let \: assume \: length \: of \: the \: pencil \: is \: x}$

$\small \red{as \: per \: que. \: portion(length) \: of \: black \: in \: pencil} = \frac{x}{8}$

$remaining \: portion = x - \frac{x}{8} = \frac{7x}{8}$

$so \: white \: portion = \frac{1}{2} \times \frac{7x}{8} = \frac{7x}{16}$

$so \: remaining \: portion = \frac{7x}{8} - \frac{7x}{16} = \frac{7x}{16}$

$\green{as \: per \: question}$

$\frac{7x}{10} = 3.5$

${\fcolorbox{pink}{white}{x = 8cm}}$

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