1. If x:y=3:5, we can choose a value for x and find the corresponding value for y. Let's say x=3, then y=5(3/5)=3.6.
Now, we can find the ratio 3x+4y : 8x+5y:
3x+4y = 3(3) + 4(3.6) = 25.8
8x+5y = 8(3) + 5(3.6) = 42.8
Therefore, the ratio is 25.8 : 42.8.
2. If x:y=8:9, we can choose a value for x and find the corresponding value for y. Let's say x=8, then y=9(8/9)=8.
Now, we can find the ratio (7x-4y) : (3x+2y):
(7x-4y) = 7(8) - 4(8) = 12
(3x+2y) = 3(8) + 2(8) = 32
Therefore, the ratio is 12 : 32, which can be simplified to 3 : 8.