Q7 of 29 Page 3

The cost of 2 kg of apples and l kg of grapes on a day was found to be Rs 160. After a month, the cost of 4 kg of apples and 2 kg of grapes is Rs 300. Represent the situation algebraically and geometrically.

Let the cost of 1 kg of apple be x and cost of 1 kg of grape be y.


Given, cost of 2 kg of apples and l kg of grapes on a day was found to be Rs 160.


∴ 2x + y = 160


Also, after a month, the cost of 4 kg of apples and 2 kg of grapes is Rs 300.


∴ 4x + 2y = 300


Now to present these equations graphically plot the points of respective lines,


For 2x + y = 160,


y = 160 – 2x


When x = 50, y = 60


When x=60, y = 40


Table is:



Plot the points A(50,60) and B(60,40)


For 4x + 2y = 300,








Plot the points C(40,–30) and D(60,30)



More from this chapter

All 29 →
5

Find the value of k for which pair of linear equations 3x + 2y = –5 and x – ky = 2 has a unique solution.

 6

John tells his daughter, ‘Seven years ago, I was seven times as old as you were then. Also, three years from now, I shall be three times as old as you will be.” Represent this situation algebraically and graphically.

 8

Solve each of the following systems of equations by the method of cross–multiplication.

x – ay = b


ax – by = c

 9

The sum of the numerator and denominator of a fraction is 12. If the denominator is increased by 3, the fraction becomes 1/2. Find the fraction.