Question

(D) 25%
3. If I purchased 11 books for Rs. 10 and sold all the books at the rate of 10 books for Rs. 11, the profit percent
is :
(A) 10%
(B) 11%
(C) 21%
(D) 100%
10​

Answer 1

$\Huge \fbox \green{Solution}$

Let the total number of books purchased be 110

Cost Price of 11 books is 10 rupees

Cost Price of 1 book will be 10 / 11 rupees

Cost Price of 110 books will be 10 / 11 × 110 = 100 rupees

Sale Price of 10 books is 11 rupees

Sale Price of 1 book will be 11 / 10

Sale Price of 110 books will be 11 / 10 × 110 = 121 rupees

$\mathfrak{Hope \: \: it \: \: Helps!}$