Find LCM of \( \frac{9}{4} \), \( \frac{21}{10} \), \( \frac{63}{20} \)
\( \frac{21}{2} \)
\( \frac{2}{63} \)
\( \frac{85}{7} \)
\( \frac{63}{2} \)
Mohan buys an old mobile for Rs. 4,000 and spends Rs. 500 on its repairs. If he sells the mobile for Rs. 5,000, then what is his profit percentage?
P can do a work in 14 days. What part of the total work can be done by P in 4 days?
\( \frac{4}{9} \)
\( \frac{2}{7} \)
\( \frac{3}{8} \)
\( \frac{6}{7} \)