Question 699607
A two digit number, where:
a = the 10's digit
b = the units
then
10a+b = the two digit number
:
" If we multiply the sum of numbers of a 2 digit number by 3, add 10 to the product, divide the outcome by 2, and subtract 11 from the quotient, we get the original number."
{{{(3(a+b) + 10)/2}}} - 11 = 10a+b
Multiply by 2 to get rid of the denominator 
3(a+b) + 10 - 2(11) = 2(10a+b)
:
3a + 3b + 10 - 22 = 20a + 2b
3a + 3b - 12 = 20a + 2b
3b - 2b = 20a - 3a + 12
b = 17a + 12
the only single digit integer for b occurs when a = -1, then b = -5
:
Find this two digit number. -15 is the original number
:
:
Check this in the original equation
{{{(3(-1-5) + 10)/2}}} - 11 = 10(-1) - 5
{{{(3(-6)+10)/2}}} - 11 = -15
{{{(-18+10)/2}}} - 11 = -15
-4 - 11 = -15