Answer:

Explanation:

Let the digit in the units place, be = y

and the digit in the tens place, be = x

So, the digit would be 10x + y

This is because, for example , 23 is not written as 2 + 3, but as 2 x 10 + 3

The number in the tens place is multiplied by 10 and then added with the digit in the units place.

CASE 1

x + y = 1/7

so, y = 1/7 - x

In the 2nd case, we have,

after interchanging, we get,

10y + x

According to the question,

10y + x = 18 - 10y + x

Rearranging the equation,

10y + 10y + x - x = 18

20y = 18

y = 18/20

  = 9 / 10

Substituting,

x + y =17

x + 9/10 = 17

x = 17 - 9/10

170 - 9 / 10

= 161 / 10

16.1

Verified answer

Answer:

History is the study of past events. People know what happened in the past by looking at things from the past including sources (like books, newspapers, scripts and letters), buildings and artifacts (like pottery, tools, coins and human or animal remains.) Libraries, archives, and museums collect and keep these things for people to study history. A person who studies history is called a historian. A person who studies pre-history and history through things left behind by ancient cultures is called an archaeologist. A person who studies mankind and society is called an anthropologist. The study of the sources and methods used to study and write history is called historiography.