Maths word problems?

1).
Jacob drove 125 km at an average speed of 80 km per hour
and 75 km at 90 km per hour.
(25/16 + 15/18) hrs = 115/48 hrs = 2 19/48 hrs
The trip took 2 hours 23.75 minutes
The average speed for the whole trip was 83 11/23 km per hour.
2).
An aircraft flies at the speed of 405 km per hour.
a)
In 25 minutes it flies a distance of 168.75 km.
b)
To fly 108 km it takes 16 minutes.
3).
Jean has a 2L bottle of orange drink,
3/5 of it is orange juice, 2/5 is water.
Jean opens the bottle and drinks 1/8 of it.
After drinking, the bottle contains 1.75L juice.
Then she fills the bottle up with water.
Water added is 1/4 L.
2(3/5 - 1/8) orange juice + 2(2/5 + 1/8) water.
19/20 orange juice + 21/20 water.
Water is 19/40 of the orange drink.

1.
Total time taken for the trip
= [(125 km)/(80 km/h) + (75 km)/(90 km/h)]
= 115/48 h
= 2 h and (19/48 h) × (60 min/h)
= 2 h 23 and 3/4 min

Average speed
= (125 + 75 km) / (115/48 h)
= 200 × (48/115) km/h
= 83 and 11/23 km/h


====
2.
a)
Distance that the aircraft flies
= (405 km/h) × (25/60 h)
= 168 and 3/4 km

b)
Time taken to fly 108 km
= (108 km) / (405 km/h)
= 4/15 h


====
3.
After Jean has drunk 1/8 of the orange drink, volume of orange juice in the orange drink
= (2 L) × (3/5) × [1 - (1/8)]
= 21/20 L

After filling the bottle with water, volume of water in the orange drink
= 2 - (21/20) L
= 19/20 L

Final fraction of the orange drink is water
= (19/20) / 2
= (19/20) × (1/2)
= 19/40