In a certain population the frequency of three genotypes is as follows
Genotype BB Bb bb
Frequency 24% 58% 18%
What is the likely frequency of B and b allele?

According to hardy weinberg principle p²+2pq+q²

Thus, BB= p², bb= q²

Frequency of B = All of BB + ½ of Bb = 24 +29 = 53%
Frequency of b = All of bb + ½ of Bb = 18 + 29 = 47%   

Hardy Weinberg equilibrium is represented by:

P ²  + q ²  + 2Pq = 1

Where P ²  is the frequency of BB genotype individuals, q ²  is the frequency of bb genotype individuals Pq is the frequency of Bb genotype individuals. 

Here, in this case,   p²  = BB,  q²  = bb, pq= Bb.

Therefore, the frequency of B is likely to be 53% and that of b is likely to be 47%

Regards.