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/sci/ - Science & Math

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2616240 No.2616240 [Reply] [Original]

Maria drove from owen Sound to Ottawa, a distance of 550km. THe trip took 7h. Maria drove at 70km/h for part of the trip, and 85km/h for hte remainder of the tirp. How far did she drive at 70km/h

Need to set up 2 equations using ax+by+c method . Anyone kno how to solve?

>> No.2616252

:E

>> No.2616280

She drove 210Km when she was going 70km/h

She drove 340 when she was going 85km/h

>> No.2616286

>>2616280
340km

>> No.2616300

Prolly dont mean this?
 x + y = 7
70 * x + 85 * y = 550
70x + 85( 7 - x) = 550
70x + 595 - 85x = 550
15x = 45
X = 3

>> No.2616321

70 km/h x + 85 km/h y = 550, and x+y=7.

x is the number of hours driven at 70 km/h. y is the number of hours driven at 85 kilometers an hour.

Once you've staged the two equations it's pretty simple stuff.

You should end up with 550=70x+85(7-x).

>550=70x-85x+595
>45=15x
>x=3

She drove (70*3=210) km at 70 km/h.