In order to build a "green city", a city actively invested in two projects: river pollution control and landscaping. It is known that it will invest100000 yuan in 20 13 years, and it is expected to invest121000000 yuan in 20 15 years. If the average annual investment growth rate is the same in these two years.

(1) Find the percentage of annual investment growth;

(2) It is known that every square meter of river pollution control needs to be invested in 400 yuan, and every square meter of landscaping needs to be invested in 200 yuan. If the total area of river pollution control and landscaping in 20 15 years is not less than 35,000 square meters, and the cost of river pollution control is not less than 4 times of the cost of landscaping, what range should the cost of landscaping be?

Solution, get: