A scooter before overhauling requires 2/3 h service time every 45 days,while after overhauling it requires 2/3 h service time every 60 days. what fraction of pre-overhauling service time is saved in the latter case?

Time required for service before overhauling = 2/3h = 40 min in 45 days
and time required for service after overhualing =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