Question

18. The sum of the digits of a two digit number is 7. If the number formed
by reversing its digits is less than the original number by 9, find the original number

19. The tens digit in a two digit number is twice the unit's digit.if 18 is subtracted
from the number, the digits are reversed. Find the number

20. A man travelled one-third of a distance by bus, two-fifth by a taxi and the remaining 28 km on scooter. How much distance did he travel​

Answer 1

18.

take the no xy. this means 10x+y( expansion form).

reverse the digits then the no is yx

yx= 10y+ x

the difference = 9x-9y

in the question the difference is given

9(x-y) = 9

so x-y =1,

sum of the digits is x+y = 7

from the 2 statement s x=4, y=3

finally the no is 43

Answer 2

she has done 18 the Q correct and Q 20 is in ur ncrt book. I had read it earlier.
here is a clue from which u might understand