SOLUTION: A boy walks at 4 km/h. There is a woman 125 metres ahead from the boy. The boy passes the woman after 15 minutes. What was the woman's speed? Thanks

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Question 944759: A boy walks at 4 km/h. There is a woman 125 metres ahead from the boy. The boy passes the woman after 15 minutes. What was the woman's speed? Thanks
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +s+ = the woman's speed in km/hr
Let hrs
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+d+=+4%2A%281%2F4%29+
+d+=+1+ km
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Convert meters to km
+125%2F1000+=+1%2F8+ km
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The woman's equation is:
+1+-+1%2F8+=+s%2A%28+1%2F4+%29+
+7%2F8+=+s%2A%28+1%2F4+%29+
Multiply both sides by +4+
+s+=+7%2F2+
+s+=+3.5+
The woman's speed is 3.5 km/hr
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check:
At her rate, in 1/4 hr, she travels +%28+7%2F2+%29%2F4+=+7%2F8+ km
+1+-+7%2F8+=+1%2F8+ km which was her head start
OK