Question

The product obtained when 13 is multiplied by 7 is
A) XXCI
B) LXI
C) XCI
D) CI

Answer 1

Hint:Here we will first multiply the given numbers and then write the result number into roman form.
Roman form is the way of writing the numerals in the form of letters like C,V,I,L and X.

Complete step-by-step answer:
The given numbers are 13 and 7
Multiplying these numbers we get:-
\[13 \times 7 = 91\]
Now since, 91 can be written as:
\[91 = \left( {100 - 10} \right) + 1\]
Also, as 100 is written as C in roman numerals
And 10 is written as X in roman numerals
1 is written as I in roman numerals.
Therefore, 91 can be written as:
Therefore, 91 can be written as:
\[91 = \left( {C - X} \right) + I\]
Now since 90 is less than 100
Therefore, X will come before C.
Hence,
\[
  91 = XC + I \\
  91 = XCI \\
 \]
Therefore, option C is the correct option.

Note:The rules for writing the roman numerals are:-
* To turn any Arabic number into a Roman numeral, break down that Arabic number into expanded notation, of units, tens, hundreds, thousands, ten of thousands, hundred of thousands, millions, etc..
* Convert each of these subgroups separately to numbers written down with Roman numerals;
* Then combine these subgroups using the additive notation to get the end Roman numeral.
The roman numeral for:
* 5 is “V”
* 10 is “X”
* 50 is “L”
* 100 is “C”