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Ratio and Proportions problem

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Ratio and Proportions problem

by The Jock » Tue Aug 18, 2009 9:04 pm
A garrison of 750 men has provision for 20 weeks, if at the end of 4 weeks, they are reinforced by 450 men, how long the provision will last?

Please solve and let me know the answer?
Thanks in advance :)
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by tohellandback » Tue Aug 18, 2009 9:24 pm
if there is one unit of food. in 4 weeks 1/5 is finished.
remaining is 4/5 units
750 men- 1 unit -eat in 20 weeks
1200 men-4/5 units -eat in 20*750/1200 *4/5
=10 weeks
so the provision lasts for 4=10=14 weeks
The powers of two are bloody impolite!!
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by PussInBoots » Wed Aug 19, 2009 3:56 pm
Not a clear question. Provision last overall, or after reinforcement? I though the question meant after reinforcement, hence 10 weeks. This is my method (thanks to one of instructors)

we have 750 * 20 = 15 000 man * week units
after 4 weeks 15 000 - 750 *4 = 12 000 man * week units
12 000 man * week / (750 + 450 ) man = 10 weeks
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Re: Ratio and Proportions problem

by arbiter » Sun Aug 23, 2009 1:58 am
The Jock wrote:A garrison of 750 men has provision for 20 weeks, if at the end of 4 weeks, they are reinforced by 450 men, how long the provision will last?

Please solve and let me know the answer?
Thanks in advance :)
For 750 men,the remaining garrison will last for 20-4=16 weeks.
1200:750 ::16:x (more men less days)

=>x=(750*16)1200=10 weeks
arbiter
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