The answer is C 16:20 because both numbers 4&5 are multiplied by four
5 .This is called the greatest common factor.
You can list all the factors(ways to divide) of each number and find the biggest one.
15'1,3,5,15
10'1,2,5,10
The greatest they share is 5
80,000going up by 10% you just add the 10% on
