Answer:
The answer is option 1.
Step-by-step explanation:
Firstly, you have to elaborate the expression :
Next you have to take out the common factors and factorize it :
Answer:
84,6km/h
Step-by-step explanation:
the whole journey was
in the first part the car travels 50km, in the second part 120km and in the third part we can find it with a simple rule of three
90km--->60 min
X<--------35min= 52.5 km the car made in the last part
50km+120km+52,5km=222.5km was all the journey
and he made it in:
- the last part in 35min,
- in the second part we know that the car was going at 80km/h and that he made 120km so:
80km--->60 min
120km--->90 min
- in the first part we know that the car was going at 25m/s and he made 50km. 25m/s*1km/1000m*3600s/1h= we obtain the speed in km/h=90km/h
90km---->60min
50km---->x=33,333 min
The whole journey last 33,333min+90min+35min=158.333min
if we express that in hour = 158.333min*1hr/60min=2.63
the car made 222.5km in 2.63 hour
so the average speed was
222.5---->2.63hr
X--------1hr=84,6
the average speed was 84,6km/h
The quotient of 2/7 is 2 ÷ 7 = 0.285714
And 3/5 is 3 ÷ 5 = 0.6
