In a single pass drilling operation, a through hole of $15 \mathrm{~mm}$ diameter is to be drilled in a steel plate of $50 \mathrm{~mm}$ thickness. Drill spindle speed is $500 \mathrm{rpm},$ feed is $0.2 \mathrm{~mm} / \mathrm{rev}$ and drill point angle is $118^{\circ} .$ Assuming $2 \mathrm{~mm}$ clearance at approach and exit, the total drill time (in seconds) is
(A) 35.1
(B) 32.4
(C) 31.2
(D) 30.1
In a single pass drilling operation, a through hole of $15 \mathrm{~mm}$ diameter is to be drilled in a steel plate of $50 \mathrm{~mm}$ thickness. Drill spindle speed is $500 \mathrm{rpm},$ feed is $0.2 \mathrm{~mm} / \mathrm{rev}$ and drill point angle is $118^{\circ} .$ Assuming $2 \mathrm{~mm}$ clearance at approach and exit, the total drill time (in seconds) is
(A) 35.1
(B) 32.4
(C) 31.2
(D) 30.1