Answer: 90%
Step-by-step explanation: To answer the question 18 is what percent of 20, we set up an equation. Let's use the variable x to represent we don't know in the equation which in this case is "what percent."
Next, we translate the question step by step into an equation. First we have 13. Next we have "is" which means "is equal to" so we write an equals sign. "What percent" is represented by the variable x, and "of" means to multiply so we multiply x times 20.
So our equation reads 18 = (x)(20)
Now to solve for x, since x is being multiplied by 20, we need to divide by 20 on both sides of the equation. On the right side of the equation, the 20's cancel and we have x. On the right side of the equation, we have 18 divided by 20 or 20 divided into 18.
Notice however that 20 doesn't divide into 18 so we need to add a decimal point and a 0 after the 18. Now, 20 divides into 180 9 times so we write a 9 in our answer above the 0 and 9 x 20 is 180 and 180 - 180 is 0 so we can stop here. Finally, bring up the decimal point and we have .9 so x = .9.
Now, remember that we want to write our answer as a percent so to change .9 to a percent, we need to move the decimal point 2 places to the right and fill the missing position with a zero and we have 90%.
This means that 18 is 90% of 20.
I have attached my long division in the image provided.