Question Video: Writing Algebraic Expressions Involving Age Mathematics • First Year of Preparatory School

Video Transcript

If a girl is 𝑥 years old, how old will she be in 20 years?

let’s start with the girl and how old she is now. Right now, she is 𝑥 years old. How old will she be in 20 years? Let’s pretend that we know how old the girl is. Let’s pretend she’s 15. If the girl is 15 years old, how old will she be in 20 years?

We have to take her age now 15 and add 20. 15 plus 20 equals 35. If we don’t know how old the girl is, how will we find how old she will be in 20 years? We follow the same process even though we don’t know how old the girl is. To find out how old the girl will be in 20 years, we take 𝑥 and we add 20. In 20 years, this girl will be 𝑥 plus 20 years old.