15:5

Simplified form: 3:1

Reason: gcd(15, 5) = 5. Divide both terms by 5 → 15/5 : 5/5 = 3 : 1.

Other ways to see it:

• As a fraction: 15/5 = 3
• As a decimal: 3.0
• If you scale the ratio, 30:10, 6:2, etc., all reduce to 3:1.