a garrison of 2000 men has provisions for 60 days . at the end of 15 days , a reinforcement arrives , and it is now found that the provisions will last only for 20 days more . what is the reinforcement ?
"2000 - - - - 60 2000 - - - - 45 x - - - - - 20 x * 20 = 2000 * 45 x = 4500 2000 - - - - - - - 1500 answer : a"
subtract(divide(subtract(multiply(2000, 60), multiply(2000, 15)), 20), 2000)