Question

14. While arranging the party, the expenses are partly fixed & partly variable according to no. of people when there are
300 people the expenses are Rs. 16,500. Now the fixed charges are decreases by 33.33% & variable charges also
decreases by 20 %. If the new expenses are 3500 less than previous one then what were the fixed charges earlier?
(a) Rs. 500
(b) Rs. 1200
(c) Rs. 1500
(d) Rs. 2000​

Answer 1

Answer:

Option C is correct.

Step-by-step explanation:

let x be the fixed charge and y be the variable charge.

Reduced Fixed price = $x-\frac{33.33}{100}x=0.6667x$

Reduced Variable price = $y-\frac{20}{100}y=0.8y$

According to the Question,

x + 300y = 16500 .........................(1)

0.6667x + 300 × 0.8y = 13000

0.6667x + 240y = 13000 ...................(2)

Now solving the system of equation we get value of x and y.

We solve them graphically.

points for equation (1),

y = 0 ⇒ x = 16500  ⇒ ( 16500 , 0 )

y = 1 ⇒ x = 16000  ⇒ ( 16000 , 1 )

points for equation (2),

x = 0 ⇒ y = 13000/240  ⇒ ( 13000/240 , 0 )

y = 0 ⇒ y = 13000/0.6667  ⇒ ( 13000/0.6667 , 0 )

From the graph, Point of intersection is ( 1500.375 , 49.99 ) ≈ ( 1500 , 50 )

x = 1500 , y = 50

Therefore, Option C is correct.

Answer 2

Answer:

option c rs.1500 is the correct answer.

Step-by-step explanation:

Let the fixed charges be rs. x & variable charges be rs. y

x +300y = 16500 _____eq(1)

Now, 33.33% =1/3 & 20%=1/5

Reduced fixed charge = x-1/3*x = 2/3x

Reduced variable charge = y-1/5*y =4/5y

New expenses are 3500 less then previous one,

16500-3500=13000

Therefore,

2/3x +300*4/5y = 13000

2/3x +240y = 13000

Multiplying all terms with 3,

3*2/3x +240y*3 = 13000*3

2x +720y = 39000

x +360y =19500_____eq(2)

Subtracting eq(1) from eq(2), we get

x=1500 & y=50