Question 803665
let Marnie's speed be x

the distance he travels when they meet is y

y/x=7
y=7x

Leslie would have driven 826-y

speed = x+18

(826-y)/(x+18) =7

substitute y

(826-7x)/(x+18)=7

826-7x=7(x+18)

826-7x =7x+126

7x+7x=826-126
14x=700
/56
x=50

Marnie's speed = 50 km/h

Leslie's speed = 50 +!8 = 68 km/h