please solve with work much appreciated

Answer:
0.046
Step-by-step explanation:
[tex]\text{BAC} = \dfrac{10N - 7.5H}{6.8 M}[/tex]
Data:
N = 4
H = 2
M = 80
Calculation:
[tex]\text{BAC} = \dfrac{10N - 7.5H}{6.8M} = \dfrac{10\times4 - 7.5\times2}{6.8\times80} = \dfrac{40 - 15}{544} = \dfrac{25}{544} = 0.046[/tex]