Question

Cost of 3 books is ₹24. What is the cost of 3 dozen books?

Answer 1

$cost \: of \: one \: book = 24 \div 3 \\ = 8 \\ number \: of \: books \: in \: a \: dozen = 12 \\ number \: of \: books \: in \: 3 \: dozens = 3 \times 12 \\ = 36 \\ cost \: of \: 36 \: books \: = 36 \times 8 \\ = 288(ans)$

Answer 2

Answer:

288 rupees

Step-by-step explanation:

Number of Books   3               3 dozen (36)

Cost                         24             x

This is in direct proportion (form is $\frac{x_{1}}{y_{1}} = \frac{x_{2}}{y_{2}}$)

Cross multiplying, we get: 3x = 36x24

                                            3x = 864

                                             x = 864 ÷ 3

                                             ∴ x = ₹288