Question

by selling 45 oranges for rupees 160, a woman losess 20%. How many oranges should she sell for rupees 112 to gain 20% on the whole?

Answer 1

Let CP be Rs x
case of loss,
SP of 1 orange = Rs 160/45
Loss = 20%
⇒SP = CP - Loss
         = x - 20% of x = x - 0.2x = 0.8x
⇒160/45 = 0.8x 
⇒x = Rs 40/9
case of gain,
Let the number of orange be y
SP of 1 orange = Rs 112/y
SP = CP + gain
      = x + 20% of x = x +0.2x = 1.2x = 1.2×(40/9)
⇒112/y = 1.2×(40/9)
⇒y = 21
so, 21 oranges should she sell for rupees 112 to gain 20% on the whole.

Answer 2

Answer:

let cp be rs x

case of loss

sp of 1 orange = Rs 160\ 45

loss = 20%

sp= cp - loss

x- 20% of x = x - 0.2 x = 0.8 x

160 \ 45 = 0.8 x

x = rs 40/9

case of gain,

let the no of orange be yr

Sp of 1 orange= rs 112/y

Sp= cp+ gain

x+ 20% of x= x+ 0.2 x = 1.2 x

1.2 x (40/9)

112/ y = 1.2 (40/9)

y= 21