If the permissible compressive and tensile stresses in a singly reinforced beam are 50 kg/cm^{2} and 1400 kg/cm^{2} respectively and the modular ratio is 18, the percentage area At of the steel required for an economic section, is

If the maximum shear stress at the end of a simply supported R.C.C. beam of 6 m effective span is 10 kg/cm^{2}, the share stirrups are provided for a distance x from either end where x is