Question

a number consists of two digits . sum of its digits is 15 .if the places of digits are interchanged then the number so obtained is 9 less than the original number . find the original number

Answer 1

let one digit x (one's plc)
anothr digit y (ten's plc)
orgnl no. 10y + x
eqn 1: x+y = 15
eqn 2: (10y + x - 9) = (10x +y)
hre r d 2 eqns...frthr it can b slvd

Answer 2

Answer:

78

Step-by-step explanation:

let tens place be x

and unit place be y

original number =10x+y

therefore x+y=15 .........i)

if the digit place is reversed

then equation will be

10y+x=(10x-y) -9

10y+y+x-10x=-9

11y+9x=-9...........ii)

9x+9y=135......iii)

x+y=15........iv)

by elimination method

-2y=126

y=126/-2

y=-63

putting the value of y in equation I)

x-63=15

x=15+63

x=78