I g of  steam at 100°C melts how much ice at O°C? (Latent heat of ice = 80 cal/gm and latent heat of steam = 540 cal/gm)

Suppose m gm ice melted, then heat required for its melting = mL = m x 80 cal. Heat available with steam for being condensed and then brought to 0°C.
= I x 540 + I x I x (100 - 0) = 640 cal
$\Rightarrow$ Heat lost = Heat taken
$\Rightarrow$ 640 = m x 80 $\Rightarrow$ m = 8gm