According to the given figure,
(a) The total number of black keys = 7
The total number of white keys = 10
Hence, the ratio of white keys to black keys on the keyboard = 10/7
(b) The total number of all keys = 10 + 7 = 17
The ratio of black keys to all keys on the given keyboard = 7/17
(c) Black keys in 1 keyboard = 7
Black keys in 14 such keyboards = 14 × 7 = 98 keys.