Question

Hi help me in this question :
A man travelled 20 km in hour , partly in car with 30 km per hour and partly in motorcycle with 18 km per hour . find the distance travelled by him in car

Answer 1

x+y=1
30x+18y=20

Answer 2

n'est-ce pas?

Answer 3

yes it is

Answer 4

but what is x and y there?

Answer 5

x is the time traveled in car, y is the time traveled in motorcycle. 30x is the distance traveled in car.

Answer 6

yes so what will be the next step ?

Answer 7

why does x+y=1?

Answer 8

x+y=1 because the amount of time traveled total is 1 hour.

Answer 9

The next step is to simply solve the system of equations. Using elimination is probably easiest.

Answer 10

ok ! let me do this

Answer 11

Or I guess actually substitution would be easy too.

Answer 12

i am getting y = \(\frac{10}{12}\)
x = 1-y = 1-\(\frac{10}{12}\)=\(\frac{2}{12}\)

Answer 13

m i right ?

Answer 14

hence the distance travelled by the car is 30 * 1/6= 5 km rright ?

Answer 15

Let's find out. If x is 2/12, then the distance traveled in car is 60/12=5 km. If y is 10/12, then the distance traveled in motorcycle is 180/12=15 km. 5+15km=20km, so it looks right to me :)

Answer 16

ok thanks a lot

Answer 17

You're welcome a lot

Answer 18

x is the time traveled in car, y is the time traveled in motorcycle. 30x is the distance traveled in car,18y is the distance in the motorcycle. x+y=1 30x+18y=20

Answer 19

Let t be the time the man traveled in a car. Solve the following for t:\[30 t+18(1-t)=20\]\[t=\frac{1}{6} \text{ hours}\]\[30*\frac{1}{6}=5 \text{ km }\]

Answer 20

distance= speed * time
you need to take time as constant unit then
\[x \div30 + (20-x)\div 18=1\] ( where x is the distance travelled by car)
solve it and you have the answer.