Satish was endowed _____ a natural talent for music.

What is the range of wavelength of electromagnetic radiation that nature has endowed our retina to detect?

At present Satish is four Madhur's age. After eight years Satish will be 2.5 times Madhur's age then. "How many times will Satish'a age be in another eight years time with respect to Madhur's age then ?