You are given a math word problem and you are supposed to make use of mathematical concepts like probability, combinatorics, linear equations, sequences/series, or simple operators like addition, subtraction, division, or multiplication to answer the given question. Choose the best option from the 5 given options and report that option.

Question: In an electric circuit, two resistors with resistances x and y are connected in parallel. If R is the combined resistance of these two resistors, then the reciprocal of R is equal to the sum of the reciprocals of x and y. What is R if x is 5 Ohms and y is 7 Ohms?

 Option A: 3/5

 Option B: 1/7

 Option C: 12/35

 Option D: 31/12

 Option E: 35/12
Option E

Question: A die is rolled twice. What is the probability of getting a sum equal to 9?

 Option A: 2/3

 Option B: 2/9

 Option C: 1/3

 Option D: 1/9

 Option E: 1/10
Option D

Question: 85% of a number is added to 24, the result is the same number. Find the number?

 Option A: 277

 Option B: 267

 Option C: 222

 Option D: 160

 Option E: 123

Option D