Question

Cost of a book is 3 more than 4 times the cost of a pen .Cost of a pen and a book together

is 43 . What is the cost of a pen and that of a book​

Answer 1

Answer:

answer in jpg

Step-by-step explanation:

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Answer 2

let the cost of a pen = x rs

and the cost of a book be = y rs

According to question,

y = 3 + 4x

4x - y = -3 ------- 1

x + y = 43

both sides multiply by 4

4x + 4y = 172 ----------- 2

equation 2 - equation 1

4x + 4y = 172

4x - y = -3

- + +

5y = 175

$y = \frac{175}{5}$

$y = 35$

substituting value of y in equation 1,

4x - (35) = -3

4x = -3 + 35

4x = 32

$x = \frac{32}{4}$

$x = 8$