Multiply the total hours by each portion:
Ally = 60 hours x 0.4 = 24 hours.
Megan = 60 x 1/4 = 60 x 0.25 = 15 hours.
Rachel and Liz = 60 hours - 24 hours - 15 hours = 21 hours total.
Rachel and Liz shared equally so 21 / 2 = 10.5 hours each.
Liz babysat 10.5 hours ( 10 and 1/2 hours).
