Final answer:
To find the original number when 3.5 percent of it is 56, you divide 56 by 0.035. The original number is 1600, corresponding to option a).
Step-by-step explanation:
To find the original number when 3.5 percent of it is 56, we need to set up a simple proportion where 3.5% (or 0.035 in decimal form) of the original number equals 56:
0.035 * original number = 56
Divide both sides by 0.035 to isolate the original number:
original number = 56 / 0.035
original number = 1600
Therefore, the original number is 1600, which corresponds to option a).