To get the
Mean, you have to add all the ages of the men together:

Next you divide

by the amount of people:
Final Answer: 26
I think true. Hope this helps!
Speed = 225 metres per minute
Distance = 15 km = 15,000 metres
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s=d/t
ts=d
Therefore: t=d/s
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Time = Distance / Speed
Time = (15,000 metres) / (225 metres per minute)
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Let's work it out:

2a + 3b = 6
5a + 2b = 4
We multiply the first equation by 5 and the second by 2 and and subtract the second from the first:
10a + 15b = 30
-10a -4b = -8
11b = 22
b = 2
2a + 3(2) = 6
2a = 0
a = 0
Checking,
5(0) + 2(2) = 4
4 = 4, true