Car speed = 630 ÷ 7 = 90km/h, truck speed = 750 ÷ 5 =150km/h.

A big truck is faster than a car.

This big truck runs very fast.

2. Xiaoming walks 300 meters in 6 minutes, and Xiaofang walks 3 minutes 180 meters. Who walks slowly?

Xiaoming speed: 300 ÷ 6 = 50m/min, and small square speed: 180 ÷ 3 = 60m/min.

Xiao Ming's speed is slower than Xiao Fang's.

Xiaoming walks very slowly.

The car travels 550 kilometers in 5 hours. According to this calculation, how many kilometers do you drive in 9 hours? How long does it take to drive 2200 kilometers?

Vehicle speed: 550 ÷ 5 =110km/h.

∴9 driving hours: 1 10× 9 = 990km.

It takes 2200÷ 1 10=20 hours to drive 2200 kilometers.

4. Naughty wanted to write a manuscript of 1200 words, and wrote 15 minutes, 20 words per minute. How many words are there?

1200-20×15 =1200-300 = 900 words.