Digital SAT Math Test 1 Question 9

A battery is being charged at a constant rate of 10mAh per minute from 2,000mAh to its full capacity of 5,000mAh . What type of function best models the relationship between the amount of energy of the battery being charged and time?
Answer:
B

Explanation

The correct answer is Choice B.

Analyze the given information to determine which type of function that best describes the amount of electrical energy being stored in the battery. Since the battery is being charged, the amount of energy stored in the battery will increase.

Therefore, “increasing linear” best models the relationship in this situation.

Choice A is incorrect because the rate at which the battery is being charged is fixed and does not vary with time.

Choices C and D are incorrect because there is no question of any decrease in the energy stored in the battery.

✨ Expert's Tip ✨

Fixed rate, i.e., fixed gradient/slope, always indicates a linear function.

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