If y varies directly as x, find the direct variation equation for the situation.
-If the resistance in an electrical circuit is held constant, the amount of current flowing through the circuit is directly proportional to the amount of voltage applied to the circuit. When 4 volts are applied to a circuit,
40 milliamperes of current flow through the circuit. Find the new current if the voltage is increased to 13 volts.
A) 52 milliamperes
B) 140 milliamperes
C) 130 milliamperes
D) 117 milliamperes

Question

Quizplus · Accepted Answer

The direct variation equation is I = kV, where I is the current, V is the voltage, and k is the constant of proportionality. Given 4 volts results in 40 milliamperes, k = 40/4 = 10. For 13 volts, I = 10 * 13 = 130 milliamperes.

If Y Varies Directly as X, Find the Direct Variation