Question

The bill for three books for ₹398.47. The first book cost ₹73.69 and the second ₹85.04.Find the cost of the third book.​

Answer 1

Answer:

Cost if 3rd Book =Rs 239.74

Step-by-step explanation:

1st book =73.69

2nd book =85.04

Bill of Three books = 398.47

So, 3rd book = 398.47-158.73

=239.74

Hope it's helpful u✌️✌️

Answer 2

Answer:

Required cost of third book is 239.74 rupees.

Step-by-step explanation:

Given, bill for three books for 398.47 rupees.

So, total cost of three books

$= 398.47 \: rupees$

and it is also given first book cost ₹73.69 and the second ₹85.04.

So,total cost of first and second book

$= (73.69 + 85.04) \\ = 158.73 \: rupees$

Now cost of third book

$= (398.47 - 158.73) \\ = 239.74 \: rupees$

This is a problem of Algebra.

Some important Algebra formulas:

${(x + y)}^{2} = {x}^{2} + 2xy + {y}^{2} \\ {(x - y)}^{2} = {x}^{2} - 2xy + {y}^{2} \\ {(x + y)}^{3} = {x}^{3} + 3 {x}^{2} y + 3x {y}^{2} + {y}^{3} \\ {(x - y)}^{3} = {x}^{3} - 3 {x}^{2} y + 3x {y}^{2} - {y}^{3} \\ {x}^{3} + {y}^{3} = {(x + y)}^{3} - 3xy(x + y) \\ {x}^{3} - {y}^{3} = {(x - y)}^{3} + 3xy(x - y) \\ {x}^{2} - {y}^{2} = (x + y)(x - y) \\ {x}^{2} + {y}^{2} = {(x - y)}^{2} + 2xy \\ {x}^{2} - {y}^{2} = {(x + y)}^{2} - 2xy \\ {x}^{3} - {y}^{3} = (x - y)( {x}^{2} + xy + {y}^{2} ) \\ {x}^{3} + {y}^{3} = (x - + y)( {x}^{2} - xy + {y}^{2} )$

Know more about Algebra,

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