Question

Xavier and Yifei have been married for exactly 37 years.Yifei is four years older than Xavier. Now the sum of their ages is 124. How old was Yifei when theywere married?a) Set up and write an equation that represents

Answer 1

Xavier's age = 23

Yifei's age = 27

Explanation:

Represent Yifei's age with Y and Xavier's age with X;

Given that the sum of their ages is 124;

X + Y = 124

Also, given that Yifei is 4 years older

Y = X + 4

Required

Find their age when they got married

From the parameters above, we've been able to form a simultaneous equation

`X + Y = 124`

`Y = X + 4`

Substitute X + 4 for Y in the first equation

`X + X + 4 = 124`

`2X + 4=124`

Subtract 4 from both sides

`2X + 4 - 4 = 124 - 4`

`2X = 120`

Divide both sides by 2

`(2X)/(2) = (120)/(2)`

`X = 60`

Substitute 60 for X in the second equation

`Y = X + 4` becomes

`Y = 60 +4`

`Y = 64`

To get their ages when they got married; we simply subtract 37 from their current ages

Xavier's age = 60 - 37

Xavier's age = 23

Yifei's age = 64 - 37

Yifei's age = 27