Question

Can someone answer this qs​

Answer 1

Step-by-step explanation:

let the price of 1 book be x

let the price of 1 pen be y

so, the equations are

4x + 10y = 100 and

7x + 9y = 158

now by substitution method,

7 (100 - 10y)/4 + 9y = 158

700 - 70y + 36y = 632

34y = 68

so, y= 2

now, 4x = 100 - 10y

4x = 100 - 20

4x = 80

x = 20

so , price of 2 books and 5 pens

= 2(20) + 5(2)

= 40 + 10

= 50

Answer 2

Answer:

50

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Step-by-step explanation:

make use of simultaneous equations to solve the answer

put books as b

put pens as p

lets create the equation :

4b + 10 p = 100

7b + 9p = 158

now make answers common

7( 4b + 10 p = 100)

= 28b + 70p = 700

4(7b + 9p = 158)

= 28b + 36p = 632

now cancel out the bs

becomes:

70p - 36p = 700-632

34p =68

p =2

now that you have p , find b

use origional equation :

4b + 10 p = 100

4b + 10(2) = 100

4b = 80

b = 20

now find the cost for 2 books and 5 pens

= 2*20 + 5*2 = 50

the cost is Rs 50

hope this helps

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