Answer:
it will take the certain particle 15/4 (unit of time) to reach 30 km/hr
Input 30 as for y and solve the equation.
Step-by-step explanation:
Since y is kilometers per hour and the question is asking for how long it takes for a certain particle to reach 30 km/hr, you input 30 for y and solve for x.
-4x + y = 15
-4x + (30) = 15
subtract 30 from both sides
-4x = -15
divide -4 from both sides
x = 15/4
it will take the certain particle 15/4 (unit of time) to reach 30 km/hr