Answer:
a) n = 3
b) every 9 cm represents 175,000 km
Explanation:
a) 20 min : 1 hour
Let's convert it into same units
⇒20 min : 60 min
÷ 20 ÷ 20
⇒ 1 : 3
So n = 3
b) 1 : 25,000
Which means every 1 cm on the map represents 25,000 km
And,
1 cm = 25,000 km
So,
9 cm = 25,000 × 9
9 cm = 175,000 km
So every 9 cm represents 175,000 km