Respuesta :
Anna spends $20 less than her father on the 500 km trip.
Given: Anna's car uses 5 Liters per 100 km
Her father's car uses 7 Liters per 100 km
Cost of petrol is $2 per Liter
Anna spends less than her father on a 500 km trip. To find by how less Anna had spent than her father.
Let's solve the question:
According to the question Anna's car uses:
5 Liters per 100 km or
100 km is travelled with 5 Liters of petrol.
Then 1 km is travelled by 5 / 100 Liters of petrol.
1 km is travelled by 1 / 20 Liters of petrol by Anna.
According to the question Anna's father car uses:
7 Liters per 100 km or
100 km is travelled by 7 Liters of petrol.
Then 1 km is travelled by 7 / 100 Liters of petrol.
1 km is travelled by 7 / 100 Liters of petrol by Anna's father.
Now 500 km is travelled by:
- Anna's car: 1 km is travelled by 1 / 20 Liters of petrol. Then 500 km is travelled by
500 × 1 / 20 Liters of petrol = 25 Liters of petrol.
Therefore 500 km is travelled by 25 Liters of petrol.
- Anna's father car: 1 km is travelled by 7 / 100 Liters of petrol. Then 500 km is travelled by
500 × 7 / 100 Liters of petrol = 35 Liters of petrol
Therefore, 500 km is travelled by 35 Liters of petrol.
Cost of petrol is $2 per Liter.
Anna: She consumes 25 Liters of petrol for the 500 km journey.
Her cost is 25 × 2 = 50
Anna's cost = $50
Anna's father: He consumes 35 Liters of petrol for the 500 km journey
His cost is 35 × 2 = 70
Anna's father cost = $70
Therefore, the difference in cost = (Anna's father cost - Anna's cost) = ($70 - $50) = $20.
Hence Anna spends $20 less than her father on the 500 km trip.
Know more about "unitary method" problems here: https://brainly.com/question/28276953
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