Answer:
3.08 km/h.
Step-by-step explanation:
We know that,
Ali traveled at a speed of s km/h for 2.5 hours.
Let d be the distance and t be the time.
...(1)
On his return journey, he increased his speed by 4 km/h and saved 15 minutes. So, distance is d and times is t-15.
...(2)
From (1) and (2), we get
Put t=40 in (1).
So, t=40 and d=100.
Now,
Total distance = d + d = 100 + 100 = 200
Total time = t + t - 15 = 40 + 40 - 15 = 65
So, the average speed is
Therefore, the average speed is 3.08 km/h.
E. 72
6 feet long cast shadow = 24 feet pole
18 feet long cast shadow = 72 feet pole
18/6=3
24x3=72
She has to go down 4, back up to 0, and then up another 4, then back to 0.I<span>f positive 1 represents the first level above ground, negative numbers are a good choice to represent levels below ground. 8 flights; starting at -4 and moving to 4.</span>
<span>–4(6x + 3) = –12(x + 10)
-24x - 12 = -12x - 120
24x - 12x = 120 - 12
12x = 108
x = 9
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