Wednesday

July 30, 2014

July 30, 2014

Posted by **Josie** on Wednesday, March 6, 2013 at 7:37pm.

I start of saying X+Y = 18. THen I turn that into X=18-Y. whats next??

thank you for helping if u can.

- algebra -
**Reiny**, Wednesday, March 6, 2013 at 8:59pmyou have to define your x and y

let the number of heavy cars be x

let the number of lighter cars be y

so, ok, at

x+y = 18

x = 18-y

5000x + 3000y = 30(2000)

divide by 1000

5x + 3y = 60

sub in your first part

5(18-y) + 3y = 60

90 - 5y + 3y = 60

-2y = -30

y = 15

There were 15 of the lighter cars, and 3 of the heavier cars

check:

15(3000) + 3(5000) = 60000 pounds = 30 tons

**Related Questions**

math - A shipment of tv sets, some weighing 30kg each and the others weighing ...

nutrition - A cancer patient recieving chemotheraphy starts 8 weeks of tx ...

math - what is 10,000lb=_____T 5 tons, since there are 2000 lb per ton. As a ...

math - A small, medium, and large sized chicken were weighing themselves on a ...

math - A small, medium, and large sized chicken were weighing themselves on a ...

math - The Egg Problem. A certain zoo kept records of the relationship between ...

operations management - Trucks are required to pass through a weighting station ...

Statistics - A stationary store has decided to accept a large shipment of ball-...

math - Find the total weight of the boxes of pecans in a shipment of 3 lb boxes ...

statistics - The weights of steers in a herd are distributed normally. The ...