SOLUTION: In a two digit positive number the unit digit is equal to the square of tens digit. The difference between original number and the number formed by interchanging the digit is 54. W
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Question 817141: In a two digit positive number the unit digit is equal to the square of tens digit. The difference between original number and the number formed by interchanging the digit is 54. What is 40% of original number? Answer by mananth(16946) (Show Source):
You can put this solution on YOUR website! In a two digit positive number the unit digit is equal to the square of tens digit. The difference between original number and the number formed by interchanging the digit is 54. What is 40% of original number?
let the number be xy
y=x^2
(10x+y)-(10y+x)=54
9x-9y=54
/9
x-y=6
substitute y=x^2
x-x^2=6
x^2-x+1/4 -1/4=6
(x-1/2)^2 =6+1/4
(x-1/2)^2=25/4
take positive square root
x-1/2 = 5/2
x=5/2+1/2
x=6/2
x=3
y=9
Number = 39
