Number Theory

Choose the Correct Answer

Correct Answer : Option c

Explanation
Let's find possible values of c:
c > 10
c is divisible by 5 but not by 10 → So c must be odd multiples of 5 over 10
So possible values: 15, 25, 35, ...
Let's try c = 15
(a) 2c = 2 × 15 = 30 → Not divisible by 4
(b) 3c = 3 × 15 = 45 → Not divisible by 4
(c) 2c + 6 = 30 + 6 = 36 → Divisible by 4
(d) 3c + 1 = 45 + 1 = 46 → Not divisible by 4
Try next: c = 25
(a) 2c = 50 → Not divisible by 4
(b) 3c = 75 → Not divisible by 4
(c) 2c + 6 = 56 →Divisible by 4
(d) 3c + 1 = 76 → Not divisible by 4
Hence, option c is correct.