Answer:
Their speed is 32 km/h.
Step-by-step explanation:
Since they're at the same speed, we can assign a variable to their speed called "x". When the first car increases its speed by 1 km/h, its new speed is "x + 1", while the other car decreases its speed by 10 km/h, so its new speed is "x - 10". The distance's formula can be expressed as below:
[tex]\text{distance} = \text{speed}*\text{time}\\[/tex]
With the modifications to their speed, the distance the first car covers in 2 h and the distance the second car covers in 3 h is shown below:
[tex]\text{distance}_{car1} = (x + 1)*2 \\\text{distance}_{car1} = 2*x + 2[/tex]
[tex]\text{distance}_{car2} = \text{speed}*\text{time}\\\text{distance}_{car2} = (x - 10)*3\\\text{distance}_{car2} = 3*x - 30[/tex]
Since the distance covered by them must be the same, we can find the value of x that makes the expressions equal.
[tex]2*x + 2 = 3*x - 30\\2*x - 3*x = -30 -2\\-x = -32\\x = 32[/tex]
Their speed is 32 km/h.
