What single decimal multiplier would you use to increase by 18% followed by a
12% decrease?

The single decimal multiplier used to increase by 18% followed by a  12% decrease is 0.21.

Step-by-step explanation:

Let 'x' be the number

As first the number has to be increased by 18%

so

Step 1: write the percentage '18%' in decimal form

18% = 0.18    

Step 2: For percentage increases: add the decimal to 1

1 + 0.18 = 1.18    

Step 3: Multiply the number x by the multiplier, found in Step 2

x × 1.18 = 1.18x

NEXT WE HAVE TO DECREASE 1.18x by 12%

Apply the same method but with a number 1.18x

12% = 0.12

1 - 0.18 = 0.18

1.18x × 0.18 = 0.21x

Therefore, the single decimal multiplier used to increase by 18% followed by a  12% decrease is 0.21.

13.33%

say 50 oranges, then 100 apples

80 are red, 20 are yellow

total fruit = 150

20chances out of 150 for yellow

20/150 = 13.33%