1/8th part of a pencil is black, half of the remaining is white. If the remaining part is blue and length of this blue part is 3 1/2cm, then find the length of the pencil ?

• A. 2
• B. 8
• C. 5
• D. 7

Answer: (B)

Let the total length of pencil = L cm Then, black part = L/8∴ Remaining part = L - L/8 = 7L/ 8 and White part = (7L/8)/2 = 7L/8∴ Remaining part = L - (L/8 + 7L/16) = 7L/16∴ length of blue part = 7L/16According to the question, 7L/16 = 31/2⇒ 7L/16 = 7/2 ∴ L =8