# Mary, who is sixteen years old, is four times as old as her brother. How old will Mary be when she she is twice as old as her brother?

##### 1 Answer

#### Explanation:

When Mary is

Let

#16 + x = 2(4+x)#

#x = 8#

Therefore, Mary will be

#16 + 8 = "24 years old"#

while her brother will be

#4+8 = "12 years old"#