Fraction - Scooter

pullagurla wrote:A scooter before overhauling requires 2/3 hour service time for every 45 days , while overhauling it requires 2/3 hour service time for every 60 days. what fraction of pre-overhauling service time saved in the latter case ?
a.4/3
b.1/3
c.1/4
d.3/4
e.4/9

before 45 days -> 2h/3
after 60 days -> 2h/3
saved time is 15 days
15/45 time is saved.
1/3
pick B

before overhauling would require service every 45,90,135,180 days..
after overhauling it would require service every 60,120,180 days..

As we can see that 180 is common in the series giving as a common ground (multiple) to compare the two

before overhauling the total time spent in service = (2/3) *60 minutes * 4 = 160 minutes
after overhauling the total time spent in service = 2/3 * 60 * 3 = 120 minutes

fraction of pre-overhauling service time saved in the latter case = 160-120 / 160 = 40/160 = 1/4 (ANSWER is D)

Here's my method:

Total time saved = 15 days.

Pre-overhauling, 45 days costs 2/3 hours of service, so 15 days would've cost 2/9 hours of service. Hence, we saved 2/9 hours.

what fraction of 2/3 is 2/9?

2/3 x = 2/9 => x = 1/3

whats the OA?