The tool life equation for HSS tool is $VT^{0.14}f^{0.7}d^{0.4}$ = constant. The tool life $(T)$ of $30 \: min$ is obtained using the following cutting conditions:
$V=45\:m/min$, $f=0.35 \: mm$, $d=2.0 \: mm$ If speed $(V)$, feed $(f)$ and depth of cut $(d)$ are increased individually by $25\%$, the tool life (in $min$) is

1. $0.15$
2. $1.06$
3. $22.50$
4. $30.0$