Long Answer TypeAftab 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'. (Isn’t this interesting?) Represent this situation algebraically and graphically.
(i) 10 students of Class X took part in Mathematics quiz. If the number of girls is 4 more than the number of boys, find the number of boys and girls who took part in the quiz.
Let cost of 1 pencil be Rs. ,v and cost of 1 pen be Rs. y
Case I. Cost of 5 pencils = 5x
Cost of 7 pens = 7y
<>According to question,
5x + 7y = 50
Case II. Cost of 7 pencils = 7x
Cost of 5 pens = 5y
According to question,
7x + 5y = 46
Thus, we have
Thus, we have following table :
Fig. 3.5.
When we plot the graph of the given equation, we find that both the lines intersect at the point (3, 5). So, x = 3,y = 5 is the required solution of the pair of linear equation.
Hence, the cost of 1 pencil be Rs. 3 cost of 1 pen be Rs. 5.
Short Answer Type
and without drawing them, find out whether the lines representing the following pairs of linear equations intersect at a point, are parallel or coincide.
and without drawing them, find out whether the lines representing the following pairs of linear equations intersect at a point, are parallel or coincide.
and without drawing them, find out whether the lines representing the following pairs of linear equations intersect at a point, are parallel or coincide.
find out whether the following pair of linear equations are consistent, or inconsistent.
find out whether the following pair of linear equations are consistent, or inconsistent.
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