A car from a to B, plan to travel 60 kilometers per hour, 5 hours to arrive. The actual speed increased by 1 / 4, then a few hours It can be reached by proportional solution

A car from a to B, plan to travel 60 kilometers per hour, 5 hours to arrive. The actual speed increased by 1 / 4, then a few hours It can be reached by proportional solution

Let x hours arrive, and if the distance remains the same, the speed is inversely proportional to the time
When the actual driving speed is increased by 1 / 4, the ratio of front and rear speed is 4:5
4：5=x：5
5x=4*5=20
x=4
A: it will arrive in 4 hours

A car from a to B, plan to travel 60 kilometers per hour, 6 hours to arrive. The actual speed is increased by one third per hour, a few hours to

60×6÷（60+60×1/3）
=360÷80
=4.5 (hours)

A bus from place a to place B can reach the destination in 6 hours as originally planned; if it first runs at the original speed of 72 km, and then increases the speed by one third, it can reach the destination 30 hours ahead of schedule
How many kilometers is the distance from place a to place B?

After variable speed = 72 × (1 + 1 / 3) = 96 km / h
Set the speed change distance to x km
X/72-X/96=0.5
X/288=0.5
X=144
Distance = 144 + 72 = 216 km