the average salary of a person for the months of january , february , march and april is rs . 8000 and that for the months february , march , april and may is rs . 8100 . if his salary for the month of may is rs . 6500 , find his salary for the month of january ?
"sum of the salaries of the person for the months of january , february , march and april = 4 * 8000 = 32000 - - - - ( 1 ) sum of the salaries of the person for the months of february , march , april and may = 4 * 8100 = 32400 - - - - ( 2 ) ( 2 ) - ( 1 ) i . e . may - jan = 400 salary of may is rs . 6500 salary of january = rs . 6100 . answer : e"
subtract(multiply(8000, const_4), subtract(multiply(8100, const_4), 6500))