Sección Cuantitativa
Ejemplo de Problems Solving
On a certain road used by the same number of trucks as cars, the truck toll was 4 times the amount of the car toll. Then the truck toll was increased by 20 percent and the car toll was increased by 25 percent. If the number of trucks and the numbers of cars using the road remained the same, by what percent did the total amount of tolls collected from these vehicles increase?
- 21
- 21.5
- 24
- 24.5
- 45
Answer: A
Explanation:
We may plug in the following values: The road is used by just 1 car and 1 truck (for the number of cars and trucks must be equal). The car toll was $20 and the truck toll was $80 (for the truck toll was 4 times the car toll). So, the amount of tolls collected was 100 (in dollars). (This is a very convenient quantity if we want to calculate a percent variation on it). Then, the new car toll is $25 (an increase of 25% on $20) and the new truck toll is $96 (an increase of 20% on $80). So, the new amount of tolls collected is 25 + 96 = 121 (in dollars). Now, it is straightforward to conclude that the percent increase on the amount of tolls collected is 21%.
Therefore, the correct answer is A.