 
 <translate> Explanation: Sum of the ages of the students = 39×15 = 585
New average = 15 years 3 months = 15 + 1414 year
Sum of the ages of students and teacher = 40×15141514 = 40×614614 = 610
Teacher age = 610 – 585 = 25 years. <ibo> Nkọwa: Nchịkọta afọ nke ụmụ akwụkwọ = 39 × 15 = 585 Nkezi ọhụrụ = afọ 15 ọnwa 3 = afọ 15 + 1414 Nchikota nke afọ nke ụmụ akwụkwọ na onye nkụzi = 40×15141514 = 40×614614 = 610 Afọ onye nkuzi = 610 <unk> 585 = afọ 25. 