Time required for service before overhauling = 2/3h = 40 min in 45 days and time required for service after overhauling =2/3h= 40 min in 60 days Now,LCM of 45 and 60 = 180 days time required for service before overhauling is 180 days = 40 x 4 = 160 min and time required for service before overhauling is 180 days =40 x 3 = 120 min ∴ fraction of time saved = 160 - 120/160 =40/160 = 1/4
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