Answer
a) 21.2 L
b) 2.11 pt
c) 0.4252 km/L
Work Step by Step
a)
$$1 \space ft^3 = 28.32 \space L$$
$$ 0.750 \space ft^3 \times \frac{28.32 \space L}{1 \space ft^3} = 21.2 \space L$$
b)
$$8 \space pt = 4 \space qt$$
$$1.057 \space qt = 1 \space L$$
$$ 1.00 \space L \times \frac{1.057 \space qt}{1 \space L} \times \frac{8 \space pt}{4 \space qt} = 2.11 \space pt$$
c)
$$1 \space gal = 4 \space qt$$
$$1 \ mi = 1.609 \ km$$
$$1 \ \frac{mi}{gal} \times \frac{1.609 \ km}{1 \ mi} \times \frac{1 \ gal}{4 \ qt} \times \frac{1.057 \ qt}{1 \ L} = 0.4252 \frac{km}{L}$$