the sum of ages of 5 children born 3 years different each is 75 yrs . what is the age of the elder child ?
"let the ages of children be x , ( x + 3 ) , ( x + 6 ) , ( x + 9 ) and ( x + 12 ) years . then , x + ( x + 3 ) + ( x + 6 ) + ( x + 9 ) + ( x + 12 ) = 75 5 x = 45 x = 9 . x + 12 = 9 + 12 = 21 e"
divide(add(add(add(add(3, const_4), add(3, const_4)), add(const_4, const_4)), 75), 5)