One more than 3 times a number is
the same as 5 times the number,
decreased by 15. find the
number.

n=15/2 or n=7.5. (their two versions of the same number. one in fraction form the other in decimal form.)

Step-by-step explanation:

(n represents 'a number' in this equasion)

3n=5n-15

3n=5n-15

3n-5n=-15 (isolate the variale)

-2n=-15

n=15/2 (a negative divided by a negative is a positive)

n=7.5