10. A part of monthly expenses of a family is constant and the remaini

1.	10. A part of monthly expenses of a family is constant and the remaining varies with the price of wheat.When the rate of wheat is Rs 250 a quintal the total monthly expenses of the family are Rs1000 .when itis Rs 240 a quintal, the total monthly expenses are Rs 980.Find the total monthly expenses of the familywhen the cost of wheat is Rs 350 a quintal.
Answer» 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

10. A part of monthly expenses of a family is constant and the remaining varies with the price of wheat.When the rate of wheat is Rs 250 a quintal the total monthly expenses of the family are Rs1000 .when itis Rs 240 a quintal, the total monthly expenses are Rs 980.Find the total monthly expenses of the familywhen the cost of wheat is Rs 350 a quintal.

Answer»

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