Question

the cost of 1 pencil and 3 erasersis rs 10 and the cost of 4 pencils and 6 erasers is rs 28.find the cost of 5 pencils and 4 erasers.

Answer 1

total amount is 28 ruppes now...



.............

Answer 2

Answer:

Rs.44

Step-by-step explanation:

Let the cost of one pencil be x

Let the cost of one eraser be y

So, cost of 4 pencils = 4x

Cost of 3 eraser = 3y

Cost of 6 erasers = 6y

Now , we are given that the cost of 1 pencil and 3 erasers rs 10

$\Rightarrow x+3y= 10$    --a

The cost of 4 pencils and 6 erasers is rs 28.

$\Rightarrow 4x+6y= 28$   --b

Solving equation a and b by substitution method .

Substitute the value of x from a in b

$\Rightarrow 4(10-3y)+6y= 28$

$\Rightarrow 40-12y+6y= 28$

$\Rightarrow 40-6y= 28$

$\Rightarrow 40-28= 6y$

$\Rightarrow 12 = 6y$

$\Rightarrow \frac{12}{6} = y$

$\Rightarrow 2 = y$

Substitute the value of y in a to get value of x

$\Rightarrow x+3(2)= 10$

$\Rightarrow x+6= 10$

$\Rightarrow x=4$

Thus the cost of one pencil is 4

Cost of 1 eraser is 6

Cost of 5 pencils = 5*4 = 20

Cost of 4 erasers = 4* 6 = 24

So, cost of 5 pencils and 4 erasers = 20+24 = 44.

Hence the cost of 5 pencils and 4 erasers is Rs.44