Question

Five books and 7 pens together cost Rs 79 7 books and 5 pens together cost
rupees 77 find the cost of two books and one pen

Answer 1

I hope this may help u

Answer 2

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HERE'S THE ANSWER..

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♠️Let the cost of one book is ( x ) and cost of one pen is ( y ) .

▶️ According to question

⏺️5 books and 7 pens together cost ₹ 79

✔️ 5 x + 7 y = ₹ 79______( 1 )

⏺️ 7 books and 5 pens together cost
₹ 77

✔️ 7 x + 5 y = ₹ 77_______( 2 )

▶️ Now multiplying 7 to Eqn ( 1 ) , and multiplying 5 to Eqn ( 2 )

✔️35 x + 49 y = 553_____( 3 )

✔️35 x + 25 y = 385______( 4 )

⏺️ Now subtracting ( 4 ) from ( 1l3 ) , We'll get

=> 35 x + 49 y = 553
=>-( 35 x + 25 y )= -385
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⏺️ 24 y = 168
___________________

=> y = 168 / 24

=> $\boxed{ y\:=\: 7}$

⏺️ Putting value of y in eqn ( 1 )

=> 5 x + 7 y = ₹ 79

=> 5 x + 7 ( 7 ) = ₹ 79

=> 5 x + 49 = ₹ 79

=> 5 x = 79 - 49

=> x = 30 / 5

=>$\boxed{ x\:=\: 6}$

▶️ So cost of one book is ₹ 6 and one pen is ₹ 7

♠️ We have to find cost of two books and one pen , so

✔️ 2 x + y = ?

=> 2 ( 6 ) + 7

=> 12 + 7

=> $\boxed{ Total \: cost\: = Rs \: 19}$ ✔️✔️

♠️two books and one pen will cost ₹ 19

HOPE HELPED..

$\red{JAI\:HIND..}$

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