Answer:
The given certain number is 17.
Step-by-step explanation:
Let the given certain number = k
So, according to the question,
2 + k = 2k - 15
or, 2 + 15 = 2k - k
or, k = 17
hence the given certain number is 17.
CHECK:
2 more than 17 = 19, and
19 is 15 less than 2 times 17
