A student spent ₹1200 on notebooks. Had each notebook cost ₹10 less, he could have bought 10 more for the same money. With x notebooks bought, this gives x^2 + 10x - 1200 = 0. How many notebooks did he buy?

Question

Accepted Answer

30. D = 100 + 4800 = 4900, √D = 70. x = -10 ± 70/2 = 30 or -40. A count cannot be negative, so he bought 30 notebooks at ₹40 each (₹30 each would have bought 40).

A student spent ₹1200 on notebooks. Had each notebook cost ₹10 less,
he could have bought 10 more for the same money. With $x$ notebooks bought,
this gives $x^{2} + 10 x - 1200 = 0$ . How many notebooks did he buy?

Step-by-Step Solution

Master this chapter in 30 minutes a day.

More Class 10 The Quadratic Formula practice

A student spent ₹1200 on notebooks. Had each notebook cost ₹10 less,he could have bought 10 more for the same money. With x notebooks bought,this gives x2+10x−1200=0. How many notebooks did he buy?

Step-by-Step Solution

Master this chapter in 30 minutes a day.

More Class 10 The Quadratic Formula practice

A student spent ₹1200 on notebooks. Had each notebook cost ₹10 less,
he could have bought 10 more for the same money. With $x$ notebooks bought,
this gives $x^{2} + 10 x - 1200 = 0$ . How many notebooks did he buy?