Explanation for Question 35 From the Math (Calc) Section on the 2019 March Sat
Question 35 says the formula above is album's law for an electric circuit 2 with current I and M peers. Potential difference V in volts and 3 resistance are in arms. A circuit has a resistance of 500 arms 4 and its potential difference will be generated by N six volt batteries that produce 5 a total potential difference of six and volts. 6 If the circuit is to have a current of no more than 0.25 ampere, 7 what is the greatest number N of six volt batteries that can be used? 8 So let's set up this equation. We know that the number of amperes is 9 your 0.25, and that that's going to be the greatest possible 10 value of the, of the current. 11 So we're going to use a greater than or equal to sine 0.25 is 12 greater than or equal to the overarm. 13 Where V is equal to six N and R is equal to 500. 14 We can multiply both sides by 500 to get 1 25 is 15 greater than or equal to six N. And then when we divide both sides 16 by six, we get 20.8, 17 three is greater than or equal to N now 18 because we can't have a partial apart of a battery. 19 The greatest number of batteries that can be used here is 20. 20 We have to round down. So the answer is.