@Kengie69@jmagsaysay2016 @PasigVersa101 If "in" po ang ginamit, the quotient would be 15 , then add ten, answer would have been 25.
But the word used is "by". So it's like saying, how many 1/2 there is in 30. The answer is 60, then add 10, that's why the correct answer is 70.