In a family there are two cars. The sum of the average miles per gallon obtained by the two cars in a particular week is 75 . The first car has consumed 25 gallons during that week, and the second has consumed 15 gallons, for a total of 1475 miles driven by the two cars combined. What was the average gas mileage obtained by each of the two cars in that week?
First car : Miles per gallon
Second car Miles per gallon
2006-10-29 12:59:22 · 6 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
25a+15b=1475
a+b=75 so b=75-a
25a+15(75-a)=1475
25a+1125-15a=1475
10a=350
a=35
35+b=75
b=40
first car gets 35 mpg
second car gets 40mpg
2006-10-29 13:03:28 · answer #1 · answered by Anonymous · 0⤊ 0⤋
a=Mileage of first car b=Mileage of second car.
a/25=MPG of first car b/15=MPG of second car
a+b=1475 this is the total mileage driven
a/25+b/15=75 this is the average miles per gallon.
Then solve. First, we solve equation 1 for a.
a=1475-b
Substitute a in the second equation.
(1475-b)/25+b/15=75
Then solve for b.
2006-10-29 13:25:33 · answer #2 · answered by Snoopy 5 · 0⤊ 0⤋
x = gas mileage of car 1 in miles/gallon
y = gas mileage of car 2 in miles/gallon
x + y = 75
25x + 15y = 1475 the number of miles travelled.
Solve the silmultaneous system, mult. top by 15
15x + 15y = 1125
25x + 15y = 1475
Subtract first from second.
10x = 350
x = 35
So, y = 40
2006-10-29 13:08:11 · answer #3 · answered by tbolling2 4 · 0⤊ 0⤋
i am not going to tell the answer but show you how
1475 divdie by 75 . that is how i would do it
2006-10-29 13:06:35 · answer #4 · answered by m 1 · 0⤊ 0⤋
Build two equations... one based on the second sentence, and the other based on the total miles driven that week.
2006-10-29 13:04:11 · answer #5 · answered by Anonymous · 0⤊ 0⤋
Are you trying to get people to do your homework for you?
2006-10-29 13:09:39 · answer #6 · answered by wenda w 2 · 0⤊ 0⤋