Can I pass 40% cooldown reduction on Kassadin's ult?

Kassadin's ult is 2 second cooldown. Adding Ultimate hunter (5% cooldown + 4% on kill) and Cosmic insight (another 5% cooldown on all abilities) is added up to 54% cooldown on just the ult. Kassadin's ult will be like 1.7 seconds. Is that right or does that no work?
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