Denise will be 25 years old in two years. Her sister, Diane, is 4 years younger. In how many years will Diane be 25 years old?
Denise is 25 - 2 = <<25-2=23>>23 years old now.
So, Diane is 23 - 4 = <<23-4=19>>19 years old now.
Diane will be 25 years old in 25 - 19 = <<25-19=6>>6 years.
#### 6