Question

The aveage cost of 20 apple and 40 orange is 12rs the average cost of 40 apple and 20 orange is rs 24 the cost of 20 apple and 20 orange is

Answer 1

20x+40y=12 eq1

40x+20y=24 eq2

add 1 and 2

20x+40y+20y+40x=24+12

60x+60y=36

divide by3

60x+60y=36

--------------------

3

20x+20y=12

Answer 2

Answer:

The cost of 20 apple and 20 orange is Rs.720

Step-by-step explanation:

Let the cost of 1 apple be x

Cost of 20 apple = 20x

Cost of 40 apple = 40x

Let the cost of 1 orange be y

Cost of 40 orange = 40 y

cost of 20 orange = 20 y

Now we are given that The average cost of 20 apple and 40 orange is 12rs

So, $12=\frac{20x+40y}{20+40}$

$12=\frac{20x+40y}{60}$

$720=20x+40y$  ---A

Now we are given that the average cost of 40 apple and 20 orange is rs 24

$24=\frac{40x+20y}{20+40}$

$24=\frac{40x+20y}{60}$

$1440=40x+20y$  --- B

Solve A and B

Plot lines A and B on graph

$720=20x+40y$  -- purple

$1440=40x+20y$  -- Green

intersection point provides the solution

So, (x,y)=(36,0)

So, Cost of 1 apple = Rs.36

Cost of 20 apple = 36*20 = Rs.720

Cost of 1 orange = Rs.0

So, The cost of 20 apple and 20 orange  = 20x+20y=20(36)+20(0)=Rs.720

Hence The cost of 20 apple and 20 orange is Rs.720