For the given problem
Let one bath towel costs x
And one hand towel cost y
Helen bought 4 bath towels and 3 hand towels for $72
so,
[tex]4x+3y=72\rightarrow(1)[/tex]Althea bought 3 bath towels and 6 hand towels of the same kind for $84
So,
[tex]3x+6y=84\rightarrow(2)[/tex]Solve the equations (1) and (2) to find x and y
Multiply equation (1) by (-2) then add to equation (2) to cross y
then solve for x
[tex]\begin{gathered} 4x+3y=72\rightarrow(\times-2) \\ 3x+6y=84 \\ ============== \\ -8x-6y=-144 \\ 3x+6y=84 \\ ============== \\ -5x=-60 \\ x=\frac{-60}{-5}=12 \end{gathered}[/tex]Substitute with x into equation (1) to find y
[tex]\begin{gathered} 4\cdot12+3y=72 \\ 3y=24 \\ y=\frac{24}{3}=8 \end{gathered}[/tex]So, the answer will be:
The cost of one bath towel = $12
The cost of one hand towel = $8