# Video: Pack 1 • Paper 3 • Question 7

Pack 1 • Paper 3 • Question 7

01:11

### Video Transcript

The ratio of Mariana’s, Vanessa’s, and David’s ages is eight to six to seven. There is a 10-year age difference between Mariana and Vanessa. How old is David?

The three parts of the ratio will be given in the same order as the names have been listed. We know that David’s age corresponds to seven parts of this ratio. So in order to work out how old David is, we need to know what one part of the ratio is worth. We are told that there is a 10-year age difference between Mariana and Vanessa.

The difference between the number of parts of the ratio that Marianna has and the number that Vanessa has is two, which means that two parts is equivalent to 10 years. We can find the value of one part of the ratio by dividing by two. One part is equal to five years.

To find David’s age, we need to multiply this by seven. So seven parts of the ratio will be equal to seven multiplied by five. David is 35 years old.