Given Expression = (.53)³ - (.42)³- 3 x .58 x .42 x (.58-.42)= a³-b³ -3ab(a - b) = (a - b)³(where a = .58 and b=.42)= (.58 - .42 )³ = .16 x .16 x .16 = 0.004096
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