Daily rent 450/60=7.5 yuan.
So Ronaldinho has to pay10× 7.5 = the rent in 75 yuan.
The rent that Xiao Li needs to pay is 20×7.5= 150 yuan.
Xiao Wang needs to pay the rent of 30×7.5=225 yuan.
Study hard, O(∩_∩)O~, you can ask again if you don't understand.