Question

Gabrielle drives her car 300 miles and averages a certain speed if the average speed has been 7 mph less she could have traveled only 230 miles in the same length time what is the average speed

Answer 1

Answer:

The average speed is 30 mph.

Step-by-step explanation:

The rate of change of distance with time is speed.

i.e Speed = $\frac{distance}{time}$

Let his average speed be represented by s.

Given that she covers 300 miles with an average speed.

So that;

s = $\frac{300}{t}$

⇒ t = $\frac{300}{s}$ .................. 1

Also, if her average speed has been 7 mph less, she could have traveled only 230 miles in the same length of time. This implies that;

(s - 7) = $\frac{230}{t}$

⇒ t = $\frac{230}{(s-7)}$ ............... 2

Thus equating 1 and 2, we have;

$\frac{300}{s}$ = $\frac{230}{(s-7)}$

230s = 300s - 2100

collecting like terms,

2100 = 300s - 230s

2100 = 70s

divide both sides by 70,

s = $\frac{2100}{70}$

 = 30 mph

The average speed is 30 mph.