Question

3. Bob, while driving to school, computes his average speed for his trip as 30 km/h. On his return trip along the
same path, his average speed is 40 km/h. What is his average speed for his whole journey?
Iculate the distance

Answer 1

Answer:

Here, 1st speed=30km/h

And 2nd speed=40km/h

Let the distance of the route be X km

So, X= v1 × T1

X=30 × T1

Again,

X= v2 × T2

X=40 × T2

Now, AV. SPEED= TOTAL DISTACE/TOTAL TIME

2X/X/30+X/40=2X/7X/120

Hence, The average speed of the whole journey is 240/7=34.2km/h

Explanation:

Hence It was helpful

Answer 2

Answer:

34.2km/hr-²

Explanation:

Assuming that Bob is travelling 'x' kilometre.

Distance = Speed * Time

(i) 1st Average speed= 30km/hr

x = v1 *t1 =30*t1

(ii) 2nd Average Speed= 40km/hr

x=v2*t2= 40*t2

v av= total distance travelled/ total time taken

v av= x+x/x/v1+x/v2

= 2x/x/30+x/40

=2x/7x/120

=240x/7x

=34.2km/hr-².

So the Average speed in his whole journey is 34.2km/hr-²