A can complete a certain work in 30 days. He started the work. After 4 days, B joined him and the whole work was completed in 10 days from the beginning. B alone can complete one-third of the same work in:
A can do a work in \( 7 \frac{1}{2} \) hours and B can do the same work in \( 10 \frac{1}{2} \) hours. If they work together for \(3 \frac{1}{2}\) hours, then what part of the work will be left out?