the sum of ages of 6 children born at the intervals of 3 years each is 75 years . what is the age of the youngest child ?
"let the ages of children be x , ( x + 3 ) , ( x + 6 ) , ( x + 9 ) , ( x + 12 ) , ( x + 15 ) years . then , x + ( x + 3 ) + ( x + 6 ) + ( x + 9 ) + ( x + 12 ) + ( x + 15 ) = 75 6 x = 30 x = 5 . age of the youngest child = x = 4 years . answer : d"
subtract(subtract(divide(75, 6), 3), 3)