Answer:
The original number was 54.5.
Step-by-step explanation:
If a number is increased by 2.8%, then it is 102.8% of it's original number.
In mathematics, "of" in virtually all cases means "multiplied by".
Therefore, we do the opposite:
1. Convert to a decimal.
102.8% = 1.028
2. Divide by the decimal.

3. Round it to the nearest tenth.
54.47 rounds to 54.5.
For example, for LCM (12,30) we find:
Using the set of prime numbers from each set with the highest exponent value we take 22 * 31 * 51 = 60. Therefore LCM (12,30) = 60.
Divide 12 by 72. this equals 6. then multiply. 7x6=47 3x6=18 and 5x6=30 there we go!
6/42 = n/7
Multiply by 7.
42/42 = n.
n = 1.
numerator = 42.