Luisa travels 25 km in 3 3 4 hours. She walks part of the way at 4 km/h and cycles the rest at 12 km/h. How far did she walk?

4 answers

distance walked --- x km
distance biked ----- 25-x km

4x + 12(25-x) = 3.75

solve for x
I got 37.0313 using your equation
But in the text book the answer is 10km
How to work it out using linear equations
I was only on my second cup of coffee when I did this ....

equation should have been
x/4 + (25-x)/12 = 3.75
multiply by 12
3x + (25-x) = 45
3x + 25 - x = 45
2x = 20
x = 10
So she walked 10 km

by linear equations:

let the distance walked be x
let the distance biked by y

x + y = 25
x/4 + y/12 = 3.75
times 12
3x + y = 45
subtract them:
2x = 20
x = 10
So she walked 10 km
this response sucks