Let the number of articles produced be x.
Therefore, cost of production of each article = Rs (2x + 3)
It is given that the total production is Rs 90.
∴ \(x(2x+3) =90\)
⇒ \(2x^2 +3x -90=0\)
⇒ \(2x^2 +15x -12x -90 =0\)
⇒ \(x(2x+15)-6(2x+15)=0\)
⇒ \((2x+15)(x-6) =0\)
Either \(2x + 15 = 0\) or \(x − 6 = 0,\)
i.e., \(x = -\frac{15}{2}\) or\(x = 6\)
As the number of articles produced can only be a positive integer, therefore, x can only be 6.
Hence, number of articles produced = 6
Cost of each article = 2 × 6 + 3 = Rs 15
Solve the problems given in Example 1:-
(i) John and Jivanti together have 45 marbles. Both of them lost 5 marbles each, and the product of the number of marbles they now have is 124. Find out how many marbles they had to start with.
(ii) A cottage industry produces a certain number of toys in a day. The cost of production of each toy (in rupees) was found to be 55 minus the number of toys produced in a day. On a particular day, the total cost of production was Rs 750. Find out the number of toys produced on that day.
Find the roots of the following quadratic equations by factorisation:
(i) \(x^2 – 3x – 10 = 0\)
(ii) \(2x^2 + x – 6 = 0\)
(iii) \(\sqrt2x^2+7x+5\sqrt2 = 0\)
(iv) \(2x^2 – x + \frac{1}8\)\( = 0\)
(v) \(100x^2 – 20x + 1 = 0\)