Question

Hi! Can anyone help me with these questions? Please and thank you!

3. A horse travels 40 kilometers per hour faster than a mule. The horse goes 360 kilometers in three hours less time than the mule goes 360 kilometers. Find the speed of each animal?
4. An airplane flies 900 miles against a headwind of 25 miles per hour. The plane took 15minutes longer for this flight than with a tailwind of 25 miles per hour. How fast could the plane fly in still air?

Answer 1

for problem (3),
let u=speed of horse in km/h and v=speed of mule in km/h,
from 1st condition,
u-v=40 .............................(a)
from second condition,
360/v-360/u=3
=>1/v-1/u=3/360=1/120 .......................(b)

solve (a) and (b),

Answer 2

for problem (4),
let u=speed of airplane in still air in miles/h, v= speed of wind in miles/h
from 1st condition,
u-v=25 ........................(a)
from 2nd condition,
900/(u-v)-900/(u+v)=15/60
=> 900/25-900/(u+v)=1/4
=> 1/(u+v)=1/25-1/4(900)
=> u+v=143/25
=> u+u-25=143/25
=> 2u=143/25+25=768/25
=> u=768/25(2)=384/25=15.36
so u=15.36 miles/h

Answer 3

Thank you!

Answer 4

welcome