Q1 of 71 Page 53

Obtain a pair of linear equations in two variables from the following information:

Father tells his son, "Five years ago, I was seven times as old as you were. After five years, I will be three times as old as you will be".

Let the present age of father = x


Let the present age of son = y


Now,


Given, Five years ago, father was seven times as old as son.


⇒ (x–5) = 7(y–5)


x – 5 = 7y – 35


= x – 7y + 30 = 0 …[1]


Also, after five years, father will be three times as old as son


⇒ (x + 5) = 3(y + 5)


x + 5 = 3y + 15


= x – 3y – 10 = 0 …[2]


eq[1] and eq[2] are required equations


More from this chapter

All 71 →
2

Obtain a pair of linear equations in two variables from the following information:

The sum of the cost of 1kg apple and 1kg pine-apple is Rs. 150 and the cost of 1 kg apple is twice the cost of 1kg pine-apple.

 3

Obtain a pair of linear equations in two variables from the following information:

Nilesh got twice the marks as obtained by Ilesh, in the annual examination of mathematics of standard 10. The sum of the marks as obtained by them is 135.

 4

Length of a rectangle is four less than the thrice of its breadth. The perimeter of the rectangle is 110.

 5

Obtain a pair of linear equations in two variables from the following information:

The sum of the weights of a father and a son is 85 kg. The weight of the son is 1/4 of the weight of his father.