The ratio of earning of A and B is 4:5. They invest their income for 1 year so that their final amount is in ratio 5:6. What will be the ratio of rate of interest?
5:6
6:5
5:4
4:5
None of these
5:4
sum: PA :PB=4:5
Amount : AA : AB = 5:6
S.I = 1:1
RA :RB = 5:4