Question

A part of monthly expenses of a family is constant and the remaining
varies with the price of rice.When the cost of rice is Rs.250 per quintal,
the monthly expenditure of the family is Rs.1000 and when
the cost of rice is Rs.240 per quintal the monthly expenditure
is Rs.980.Find the monthly expenditure the family when
the cost of price Rs.300 per quintal.
(class 10 CBSE SAMPLE PAPER 2017-18 MATHS)

Answer 1

Let the constant expenditure be ₹.x

Let the consumption of rice by the family be y quintals.


x+250y=1000------------------(1)


x+240y=980-------------------(2)


Subtracting eq (1)and(2)


x + 250y =1000

x + 240y = 980

(-)  (-)      (-)

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

10y = 20


y= 20/10


y= 2………….(3)


Put the value of y in eq 1


x+250y=1000


x + 250(2) = 1000


x+ 500 = 1000


x= 1000-500


x=500………….(4)



Total  monthly expenditure when the cost of rice ₹300 = constant expenditure +  consumption of rice at ₹ 300 per quintal.


= x+300y


= 500 + 300 × 2


( From eq 3 & 4)


= 500+ 600


= ₹ 1100


Hence, the Total  monthly expenditure when the cost of rice ₹300 is ₹ 1100


Hope this will help you....

Answer 2

Answer:

Step-by-step explanation:

The question is different..but method is same