 
 <translate> There are 10 x 3 = 30 green chairs. The total number of blue and green chairs is 10 + 30 = 40. So, there are 40 - 13 = 27 white chairs. Therefore, there are 40 + 27 = 67 chairs in a classroom. Final answer: 67. <hau> Akwai 10 x 3 = 30 koren kujeru. Jimlar adadin kujerun shuɗi da kore shine 10 + 30 = 40. Saboda haka, akwai 40 - 13 = 27 fararen kujeru. Saboda haka, akwai kujeru 40 + 27 = 67 a cikin aji. Amsar ƙarshe: 67. 