Question

First number is 45% less than third number, second number is 20% more than third number
then average of first two numbers is how much percent less than third number?

Answer 1

Answer:

12.5%

Step-by-step explanation:

We let the 3 numbers be x, y, and z

We know that the first number is 45% less than the third so our list is:

0.55z, y, z

Since the second number is 20% more than the third number our list becomes

0.55x, 1.2z, z

The average of the first 2 are

(1.2z + 0.55z)/2 = 0.875z

We use the percent change formula

(new number-old number)/old number x 100

Our old number is z and our new number is 0.875z

Solving this gets -12.5, since the sign is negative, we know that this means percent decrease so 12.5% decrease

Answer 2

Answer:

Let the third number be 100

Step-by-step explanation: According to question

Third number is 100

First number is 100-100*45/100= 100-45=55

Second number is 100+100*20/100= 100+20=120

Average of the first number and second number

= 55+120/2=175/2=87.5

Required Percentage Less:- 100-87.5/100*100

=12.5%