Question

A two-digit number is 4 times the sum of its digits. If 18 is added to the number, the digits
are reversed. Find the number.
[CBSE 2001C)

Answer 1

Answer:

a two digit number is 4 times the sum of it's digit so,

10x + y = 4(x +y)

if 18 is added to the number, digits get reversed so,

18 + 10x + y = 10y + x

18 + 10x - x = 10y - y

18 + 9x = 9y

divide by 9 on both sides

2 + x = y (substitute y in first equation)

10x + (x + 2) = 4(x + (x + 2))

10x + x + 2 = 4x + 4(x + 2)

11x + 2 = 4x + 4x + 8

11x - 8x = 8 - 2

3x = 6

x = 2

y = x + 2 = 2 + 2 = 4

so the two digit number is 10x + y = 10*2 + 4 = 24

Step-by-step explanation:

Answer 2

24

this is the steps for the answer