Lingling built a house with sticks. She built three rooms with 13 sticks. At this rate, how much will it cost to build eight rooms? Root, take n rooms?

Because she needs 13 to build three rooms.

Therefore, if she builds eight rooms, she needs X.

Then 3: 13 = 8: x

3x= 104

X=34.67≈35 (root)

A: It takes 35 to build 8 houses.

Need n rooms

3: 13=n:x

3x= 13n

x= 13n/3

Answer: it takes 13n/3 to select n rooms.