The sum of the digits of a two-digit number is 6. when the digits are reversed, the number decreases by 18. find the original number.

Explanation:

Let the digits be a and b.

The sum of the digits of a two-digit number is 6

That is

         a + b = 6

When the digits are reversed, the number decreases by 18

             ab - ba = 18

We need to find the number

Since ab - ba = 18, we know that a is greater than b.

Take a = 4

                4 + b = 6

                      b = 6 - 4 = 2

 That is the number is ab = 42

  When it is reversed the number is 24.

              42 - 24 = 18, hence correct

The number is 42          

the answer is 12 as i may remember

: )

it is given that trillions of microbes make up to 1% to 3% of the body mass.

let's take average of this percentage: 2%

consider the average mass of the human body as 70 kg.

then, trillions of microbes would have mass  

therefore, 100 trillion micro-organisms would weigh:

this is an approximate value and could change depending on the mass of the human body and percentage of the microbes present in it.

average mass per microorganism =