A can do a work in 15 days and B in 20 days. They work on it together for 4 days, then the fraction of the work that is left is -
অপশনসমূহ (Options)
সঠিক উত্তর চিহ্নিত
ক
1/4
খ
1/8
গ
1/15
ঘ
8/15