Question

A TWO DIGIT NUMBER IS 4 TIMES THE SUM OF DIGITS IN IT.IF 27 IS ADDED TO THAT NUMBER,THE DIGITS ARE REVERSED.FIND THE NUMBER.


A - 24
B - 36
C - 48
D - 63

Answer 1

let unit place= a and tens place=b
number= a*1+b*10
so, a*1+b*10=4(a+b)
a+10b=4a+4b
6b=3a. 2b=a
now,(a+10b)+27=10a+b
9b +27=9a
put a=2b, 9b+27=9*2b
9b+27=18b
27=9b
b=3
a=2b=2*3=6, a=6
hence number=3*10+6*1=36. answer is B

Answer 2

Let the number be x
now 2 digit number is x+x=2x
if 27is added to 2x and number is reversed it means 72
as per question,
2x+72=4x
72=4x-2x
72=2x
72/2=x
36=x