a garrison of 400 men had a provision for 31 days . after 20 days 180 persons re - enforcement leave the garrison . find the number of days for which the remaining ration will be sufficient ?
"400 - - - 31 400 - - - 11 220 - - - ? 400 * 11 = 220 * x = > x = 20 days . answer : c"
divide(multiply(subtract(31, 20), 400), 180)