Tag: mental multiplication

Questions Related to mental multiplication

Find the value of $\displaystyle\left(\frac{P+Q}{R}\right)\times S$.
(i) $100$ lakhs $=$ _________[Q] millions
(ii) ____[R] crores $=100$ millions
(iii) $100$ thousands $=$ ___[P] lakhs
(iv) $10$ crores $=$ _______[S] millions.

maths ways to multiply and divide mental multiplication multiplication methods multiplication of numbers

  1. $10$

  2. $100$

  3. $110$

  4. $1$

Show answer
Correct Option: C
Explanation:
$1$ Million $=$ $10$ lakh
$100$lakh $=$ Q million
Q $=$ ($100$/$10$) $=$$10$
R crore $=$ $100$ Million
R $=$ ($100$X$1000000$) / ($10000000$)
R $=$ $10$
$100$ X $1000$ $=$ $1$lakh $=$ P lakhs
P $=$ $1$
$10$X$10000000$ $=$ S Million
S $=$ $100000000$/$1000000$
S $=$  $100$
So, P $=$ $1$,   Q $=$ $10$,  R $=$ $10$,  S $=$ $100$
P $+$ Q  $=$ $11$
$\dfrac{(P+Q)}{R}=$ $11/10$
$\left(\dfrac{(P+Q)}{R}\right)\times S=\dfrac{11}{10}\times 100$ $=$ $110$
Hence, option C is correct.