1:1,5

2:3

Explanation:

• 1:1,5 means 1 to 1.5 (decimal comma).
• To clear the decimal, multiply both parts by 2: 1×2 : 1.5×2 = 2 : 3.
• So the simplified integer ratio is 2:3. (Also: 1 is 2/3 of 1.5; 1.5 is 1.5 times 1.)