Posted by **jenna** on Sunday, March 25, 2012 at 3:55pm.

A farmer wants to fence in 60 000m^2 of land in a rectangular field along a straight road. The fencing that he plans to use along the road is $10 per meter and the fencing that he plans to use for the other three sides costs $5 per meter.

a) How much of each type of fence should he buy to keep his expanses to a minimum?

b) What is the minimum expanse?

- 11th grade math -
**Reiny**, Sunday, March 25, 2012 at 5:53pm
width of field --- x

length of field --- y , with y as the distance along the road

xy = 60000

y = 60000/x

cost = 5(2x+y) + 10y

= 10x = 15y

= 10x + 15(60000/x)

= 10x + 900000/x

d(cost)/dx = 10 - 900000/x^2 = 0 for a min of cost

10x^2 = 900000

x^2 = 90000

x = √90000 = 300

then y = 60000/300 = 200

so the field should be 200 m by 300 m , with the 200 metres along the road

minimum expense = 10x+ 15y = 3000 + 3000 = $6000

- 11th grade math -
**Anonymous**, Wednesday, March 28, 2012 at 9:36pm
There were 27 students who completed a survey. There were 14 boys and 13 girls. One survey was picked at random. To the nearest hundredth, what is the probability it was completed by a girl?

- 11th grade math -
**kathy**, Tuesday, May 15, 2012 at 8:02am
13/27

- 11th grade math -
**gina**, Friday, October 19, 2012 at 9:09pm
read3books4minits. Idonotnoaboutfillchrips.butmabesomere

time.readyourbooks

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