Question

if the cost of bananas is increased by rs 10 per dozen one can get 3 dozens less for 600 find the original cost of bananas​

Answer 1

Answer:

Let x be the original cost of a dozen bananas. For Rs.600 let us one gets y dozens.

xy = 600 … (1)

(x+10)(y-3) = 600 … (2)

From (1) y = 600/x. Putting that value in (2), we get,

(x+10)(600/x-3) = 600 or

(x+10)(600–3x)/x = 600 or

(10+x)(600 -3x) = 600x or

6000 + 570x - 3x^2 = 600x or

6000 - 30x - 3x^2 = 0 or

2000 - 10x - x^2 = 0

x^2 + 10x - 2000 = 0

(x+50)(x-40) = 0

So x = -50 or 40. Since cost of bananas cannot a negative figure, x = 40.

So at Rs.40 per dozen one can buy 15 dozens for Rs.600. If the cost goes up by Rs.10, the person can get 600/(40+10) = 600/50 = 12 dozens which is 3 dozens short of the previous purchasing power!

So the original cost of bananas is Rs.40 per dozen.

Step-by-step explanation:

Answer 2

Answer:

Step-by-step explanation:

Let the cost of bananas be X/dozen

ACC .to given condition

600/x-600/X+10=3

600(1/x-1/X+10)=3

600{x+10-x/X(X+10)}=3

600{10/x^2+10x}=3

600=3{x^2+10x}/10

6000=3x^2+30x

Dividing by 3

x^2 +10x-2000=0

x^2-50x+40x-2000=0

x(x-50)+40(x-50)=0

x=50 or x=-40

x is not equal to -40

Therefore ....X=50

The original cost of bananas is 50 per dozen