What number is that, to which if 1, 5, and 13, be severally added, the first sum shall be to the second, as the second to the third? Choose the correct choice from the following options
A) 1
B) 2
C) 3
D) 4
E) 5

Rationale: solution let x = the number required . by the conditions , x + 1 : x + 5 = a + 5 : x + 13 subtracting terms , ( art . 385,2 . ) x + 1 : 4 = x + 5 : 8 therefore 8 x + 8 = 4 x + 20 . and x = 3 . answer c
Answer: C