On a full sized piano their are 36 black keys and 52 white keys express the ratio black keys to whtie keys as a fraction in simplest form explane its meaning

Black keys : white keys

b : w =  36 : 52

b : w =  18 : 26  =  9 : 13

b : w  = 9 : 13

Total ratio =  9 + 13 = 22.

It means for every 9 black keys you have 13 white keys.

It also means for the piano the fraction of black keys is  9/22 of the entire piano

It also means for the piano the fraction of white keys is  13/22 of the entire piano