Question

450 रुपए में कुछ टैनिस बॉल खरीद गए यदि प्रत्येक बॉल १५ रूपए सस्ता होगा तो उतने ही राशि में ५ बॉल ओर खरीदे जा सकते थे खरीदे गए बॉल की संख्या ज्ञात कीजीए​

Answer 1

Answer:

10 balls

Step-by-step explanation:

Let x be the number of balls.

Cost of x balls = 450

Cost of 1 ball = 450/x

Now if the price is reduced by 15, 5 more balls can be bought in the same price.

i.e. 450/x - 15 = 450/(x+5)

450/x = 450/(x+5) + 15

30/x = 30/(x+5) + 1 (dividing by 15 on both sides)

30/x = (30+x+5)/(x+5)

30x + 150 = 30x + x^2 + 5x

x^2 + 5x - 150 = 0

x^2 + 15x - 10x - 150 = 0

x(x+15) - 10(x+15) = 0

(x-10)(x+5) = 0

x = 10 x = -15

since number can't be negative, X = 10