Late at one speed, early at another: distance

The same question, asked 2 times: 13 Sep 2025 S2*, 15 Sep 2025 S3. Every wording below, oldest first.

Try each one first, then open its answer.

Question 1
13 Sep 2025 S2
70 $A person travels from city A to city B. If he travels at a speed of 50 km/h, he arrives 1 hour early. If he travels at a speed of 30 km/h, he arrives 1 hour late. What is the distance (in km) between city A and city B?$
Tap an option to check your answer.
Question 2
15 Sep 2025 S3
69 $A student walks from his home to school at a speed of 4 km/h and reaches 15 minutes late. If he increases his speed to 6 km/h, he reaches 5 minutes early. What is the distance (in km) from his home to school?$
Tap an option to check your answer.

Question 1