Let c be the specific heat of the metal.
Heat gained by the metal
Q = m c Δt
Q = 60 × c × (100 – 20)
Q = 60 × c × 80 cal
The heat released by the steam
Q = m × L
Q = 0.5 × 540 cal
By the principle of mixtures,
Heat given is equal to Heat taken
0.5 × 540 = 60 × c ×80
c = 0.056 cal/g ∘C