Question

Cost of 3 pencils is equal to the cost of 1 pen and cost of 1 pen and cost of 2 pens, 6 pencils and 1 book is rupees 89 and the cost of 1 pen, 18 pencils and 5 books is rupees 367. Find the cost of 3 pens, 3 pencils and 1 book

Answer 1

after pics continues here...
3pens+3pencil+1book= 3×6+3×2+65= 18+6+65=₹89

Answer 2

Answer:

Cost of 3 pens, 3 pencils and 1 book is Rs.89.

Step-by-step explanation:

Given : Cost of 3 pencils is equal to the cost of 1 pen and cost of 2 pens, 6 pencils and 1 book is rupees 89 and the cost of 1 pen, 18 pencils and 5 books is rupees 367.

To find : The cost of 3 pens, 3 pencils and 1 book?

Solution :

Let the cost of the pencil be x.

The cost of pen be y.

The cost of notebook be z.

According to question,

Cost of 3 pencils is equal to the cost of 1 pen.

i.e. $y=3x$ .....(1)

Cost of 2 pens, 6 pencils and 1 book is Rs.89

i.e. $2y+6x+z=89$ .....(2)

Cost of 1 pen, 18 pencils and 5 books is Rs.367.

i.e. $y+18x+5z=367$ .....(3)

Now, Solving equation (1),(2) and (3)

Substitute y from (1) in (2) and (3),

$2(3x)+6x+z=89$

$12x+z=89$ .....(4)

$3x+18x+5z=367$

$21x+5z=367$ .....(5)

Multiply (4) by 5 and then subtract equation (5) from it,

$60x+5z-21x-5z=445-367$

$39x=78$

$x=\frac{78}{39}$

$x=2$

Substitute in equation (1),

$y=3(2)=6$

Substitute the value of x and y in (2),

$2(6)+6(2)+z=89$

$12+12+z=89$

$z=65$

So, The cost of pencil is 2, pen is 6 and book is 65.

Now, Cost of 3 pens, 3 pencils and 1 book.

3 pens = 3×6= 18

3 pencil = 3×2= 6

1 book = 1×65= 65

Total cost is 18+6+65=89.

Therefore, Cost of 3 pens, 3 pencils and 1 book is Rs.89.