Question 1124228


Let {{{x}}} be the rate (the speed) of the slower motorboat, in miles-per-hour.

Then the rate of the faster motorboat is {{{(x+9)mph}}}.

the distance {{{d=r*t}}}

after {{{2h}}}:

{{{d=2x}}}->the slower motorboat
{{{d=2(x+9)}}}->the faster motorboat 

since they travel in opposite directions, you need to add {{{2x+2(x+9)}}} to get how par the boats are apart

since given that the boats are {{{170}}} miles apart, your equation is

{{{2x + 2(x+9) = 170}}}


Simplify and solve the equation for {{{x}}}:

{{{4x + 18 = 170}}} 

{{{4x = 170 - 18}}} 

{{{4x = 152}}} 

{{{x = 152/4 = 38}}} 

 The speed of the {{{slower}}} motorboat is {{{38mph}}}. 
The speed of the faster motorboat is {{{38+9 = 47mph}}}.