A spring balance reads w₁ when a ball is suspended from it. A weighing machine reads w₂ when a tank of liquid is kept on it. When the ball is immersed in tank, the spring balance reads w₃ and the weighing machine reads w₄. Then which of the following is correct

Let m be the mass of ball & M be the mass of tank then w₁ = mg; w₂ = Mg; w₃ = mg - F_B w₄ = mg + F_B As ball experiences an upward force F_B the reading of spring balance will reduce ball exerts a reaction force F_B on tank so reading of weighing machine increases. 
$\therefore$w₄>w₂; w₁>w₃