For a certain job, the cost of metal cutting is Rs. 180

For a certain job, the cost of metal cutting is Rs. 180 C/V and the cost of tooling is Rs. 270 C/ (TV), where C is a constant, V is the cutting speed in m/min and T is the tool life in minutes. The Taylor's tool life equation is VT^0.25 = 150. The cutting speed (in m/min) for the minimum total cost is________.

L_m =	18C
	V

C_g =	270C
	TV

VT^0.25 = 150

V_opt = V = C		n	L_m			ⁿ
		1 - n	C_g

= 150		0.25	×	18	T		^0.25
		1 - 0.25		270

= 150		1	×	18	×	150⁴		^0.25
		3		270		V⁴

= 150(57.914) ×			T₁		^0.25
			V⁴

V = 150 × 57.914 ×	1
	V

V² =150 × 57.914
V = 93.2 m/min