Need Help ASAP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

tesha05

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Sep 7, 2005
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Please show the work

1. A father is four times as old as his daughter. In 6 years, he will be three times as old as she is. How old is the daughter now?

2. The fuel consumption of William's car is 30 miles per gallon on the highway and 25 miles per gallon in the city. On a vacation trip of 400 miles he used 14 gallons of gas. How many highway miles did he drive on this trip?
 
father = x
daughter = y

x =4y

x+6 = 3(y+6)

now sub in x=3y to the second equation and solve
 
tesha05 said:
2. The fuel consumption of William's car is 30 miles per gallon on the highway and 25 miles per gallon in the city. On a vacation trip of 400 miles he used 14 gallons of gas. How many highway miles did he drive on this trip?
Pick a variable to stand for the number of miles he drove on the highway (say, "h").

You know he drove 400 miles in total. If he drove 50 miles on the highway, how many miles did he drive in the city? If he drove 75 miles on the highway, how many miles did he drive in the city? If he drove 100 miles on the highway, how many miles did he drive in the city?

If he drove "h" miles on the highway, how many miles did he drive in the city?

Considering gas-mileage, if he drove 30 miles on the highway, at 30 mpg, how many gallons did he use? What if he drove 60 miles on the highway? How about 90 miles?

If he drove "h" miles on the highway, how many gallons did he use?

Following the same reasoning, find an expression for the number of gallons used while driving in the city.

Add the two "gallons used" expressions, and set equal to "14". Solve.

If you get stuck, please reply showing how far you hav gotten. Thank you.

Eliz.
 
highway distance= a
city distance = b

(a/30) + (b/25) = 14

a+ b = 400
a=400-b

now combine the 2 equations using a =400-b in the first equation
 
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