Subtract the 17190 from the 21840. you get 4650. 4650 divided by 21840 is 0.21. The percent decrease is 21%
The answer is none. Since you have to add your a's first, your left with 0 meaning that there is no more a's meaning that you have no solution. Hope this helps!
ANSWER
1. Multiply the fraction by 5/5 to get a denominator of 100 and then write the numerator as hundredths using a decimal point.
EXPLANATION
Renaldo wants to write

as a decimal.
He needs a denominator of 100, so he can multiply by

to obtain:

This will be

He can now obtain the decimal equivalent as

The correct choice is option 1.
1.2 is the answer to your question.