A memorial trust donates Rs. 5,00,000 to a school, the interest on which is to be used for awarding 3 scholarships to students obtaining first three positions in the school examination every year. If the donation earns an interest of 12 per cent per annum and the values of the second and third scholarships are Rs. 20,000 and Rs. 15,000 respectively, find out the value of the first scholarship.