পেট্রোবাংলা প্রিলি ও লিখিত সমন্বিত প্রস্তুতি [Archived]
The ratio of Sara's age 4 years ago and Vaishali's age after 4 years is 1 : 1. Presently, the ratio of their ages is 5 : 3. Find the ratio between Sara's age 4 years hence and Vaishali's age 4 years ago.