Shantanu completes 5/8 of a job in 20 days. At this rate,

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Shantanu completes 5/8 of a job in 20 days. At this rate, how many more days will he take to finish the job ?

1. 6 days
2. 18 days
3. 5 days
4. 12 days

Correct Option: D

Let the required number of days be N.
Remaining work = 1 - 5/8 = 3/8
Less work, Less days (Direct proportion)
5/8 : 3/8 : : 20 : N
⇒ N = (3/8) x 20 x 8/5
∴ N = 12 days