Calculusss Helppp!! Urgent..please help with this one. i tried every method i know, keep getting it wrong. help out!!!

Question

A road running north to south crosses a road going east to west at the point P. Car A is driving north along the first road, and car B is driving east along the second road. At a particular time car A is 10 kilometers to the north of P and traveling at 50 km/hr, while car B is 15 kilometers to the east of P and traveling at 120 km/hr. How fast is the distance between the two cars changing?

___ km/hr

i got 127.6 k/hr which is wrong and 44.26 km/hr which is also wrong please help out!!!.

Answer 1

Let y be the position of Car A, and let y be the position of Car B.

Let d be the distance between the two cars.

Then d² = 10² + 15² = 100 + 225 = 325

d = √325 = 5√13

(d²)' = 2d * d' = 2d' * 5√13

d = x² + y²

(x² + y²)' = 2xx' + 2yy'

Dividing both sides by 2,

dd' = xx' + yy'

d' = (xx' + yy')/d

d' = (15*120 + 10*50)/d = (1800 + 500)/d

d' = (2300)/(5√13) = 460/√13

d' = 460*√13/13 ≈ 127.58 km/hr

Does the complete problem ask for 2 decimal places of accuracy? 127.58 km/hr

Do you need an exact answer? 460*√13/13 km/hr

Answer 2

d^2=s^2+e^2

dd'=ss'+ee'

d'=(ss'+ee')/d

= (-50(10)+120(50))/d

= (-500+6000)/sqr(2500+100)= 5500/10sqr26= 550/sqr26

d' = about 107.864 km/hr

127.5 kph would be correct if the 1st car were going north, not south