Drop the "S".

65

Broommates!

171

Four cats, each near the tail of a cat in an adjacent corner

1 apple costs $0.18 and 1 banana costs $0.14.

Train.

Orange

Because seven eight (ate) nine

Use Roman Numerals (numbers):

49 = XXXXIX 1= I

Remove the I from XXXXIX gives you XXXXX (50)

XXXXIX (29) - I (1) = XXXXX (50)

She was returning an overdue library book.

51 and 15,
42 and 24,
or
60 and 06.