Answer:
The number of messages sent by Justin was [tex]180\ messages[/tex]
The number of messages sent by David was [tex]270\ messages[/tex]
Step-by-step explanation:
Let
x-----> number of messages sent by Justin
y----> number of messages sent by David
we know that
[tex]\frac{x}{y}=\frac{8}{12}[/tex]
[tex]x=\frac{8}{12}y[/tex] ----> equation A
[tex]x+y=450[/tex] -----> equation B
substitute equation A in equation B and solve for y
[tex]\frac{8}{12}y+y=450[/tex]
[tex]\frac{20}{12}y=450[/tex]
[tex]y=450*12/20=270\ messages[/tex]
Find the value of x
[tex]x=\frac{8}{12}(270)=180\ messages[/tex]
therefore
The number of messages sent by Justin was [tex]180\ messages[/tex]
The number of messages sent by David was [tex]270\ messages[/tex]
