V1 = Volume of bubble at 60m below water surface = 4πr³/3 = (4×3.142×3×3×3)/3 = 113.112cm³
P1 = Pressure at 60m below water surface = 10+60 = 70m of water.
P2 = Pressure at just below water surface = 10m of water.
V2 = Volume of bubble just below water surface = ?
Using P1V1 = P2V2 (BOYLE'S LAW)
70×113.112 = 10×V2
V2 = 7×113.112 = 791.784cm³ (ANSWER)