The binding constraints for this problem are the first and second.

Min. A $+2$B

s$.$t$.$

A $+$ B $>=300$

$2$A $+5$B $<=750$

$2$A $+$ B $>=400$

A$,$ B $>=0$

$*$ Denote, coefficient for B is c$2,$ and coefficient for A is c$1.$

$1)$ Keeping c$2$ fixed at $2,$ over what range can c$1$ vary before there is a change in the optimal solution point?

$2)$ Keeping c$1$ fixed at $1,$ over what range can c$2$ vary before there is a change in the optimal solution point?

$3)$ If the objective function becomes Min $1\mathrm{.}5$A $+2$B$,$ whatwill be the optimal values of A$,$ B and the objective function?