A, B and C can finish a work independently in 10, 12 and 15 days. C starts the work and after 1 day, B joins him. After 1 day of B, A also joins them but leave 3 days before completion of the work, while B left two days before completion of work. What will be the total number of days taken to complete the work?
There is something I don't understand about algebra: It has been around for thousands of years, yet no one has ever found out what the value of "x" or "y" really is.