A, B & C are partners sharing profits in ratio of 1/2:2/5:1/10. If C retires then what will be the new ratio between the remaining partners?

5:4

Old ratio 1/2:2/5:1/10 = 5:4:1
If C retires then the new ratio will be 5:4 because if the gaining ratio is not given and only the old ratio is given then the old ratio becomes the new ratio.