Question

the sum of a two digit number is 12 if the digits are reversed the new number becomes 4 by 7 times the original number find the original number​

Answer 1

Answer:

Step-by-step explanation:

here you go ☆☆

▪let digit at ones place = x

and at tens place= y

▪so, no. is 10y + x

▪given, y+x= 12------《1》

▪if no. is reversed , then

▪10x+ y = 4/7(10y +x)

▪10x-4/7x + y -40/7y

66/7x-33/7y = 0

▪multiply term with 7 , we get ,

▪66x -33y = 0

taking 33 as common,

▪2x -y =0------《2》

▪by elimination method,

multiply 1 by 2 and subtract 2 from 1 ,we get,

▪2x +2y =24

▪2x - y = 0

- + -

▪3y = 24

▪y = 8

▪so x= 4

▪so original no.= 84

hope it helps you....

Answer 2

Answer:

Let the two digit number be 10x+y

Sum of digit : x+y=12 __(i)

A.t.Q : 2(10x+y)−(10y+x)=12

⇒20x+2y−10y−x=12

⇒19x−8y=12

⇒19x−8y−12=0 __(ii)

Put eq. (i) in eq. (ii)

⇒19(12−y)−8y−12=0

⇒228−19y−8y−12=0

⇒27y=216

⇒y=8

x+y=12

x=12−8

x=4

Number : 48