6. A number consists of two digits, whose sum is 9. If the digits are

1.	6. A number consists of two digits, whose sum is 9. If the digits are reversed, the new number isnumber. Find the numberof the first
Answer» Let the no. is 10x + y x + y = 9 eq1 10y +x = 3/8 (10x +y) 80y + 8x = 30x + 3y 80y -3y = 30x - 8x 77y = 22x Now from eq1 put x = 9 - y 77y = 22(9 - y) 77y = 198 - 22y 99y = 198 y = 2 put y in eq1 x + y = 9 x + 2 = 9 x = 7 Number is 10x + y 10×7+2= 70 + 2 72 is the Number

6. A number consists of two digits, whose sum is 9. If the digits are reversed, the new number isnumber. Find the numberof the first

Answer»

Let the no. is 10x + y

x + y = 9 eq1

10y +x = 3/8 (10x +y)

80y + 8x = 30x + 3y

80y -3y = 30x - 8x

77y = 22x

Now from eq1 put x = 9 - y

77y = 22(9 - y)

77y = 198 - 22y

99y = 198

y = 2

put y in eq1

x + y = 9

x + 2 = 9

x = 7

Number is 10x + y

10×7+2= 70 + 2

72 is the Number