Question

the price of 80 apple is equal to that of 120 oranges. The prices of 60 apples and 75 oranges together is Rs. 1320 . The total prices of 25 apples and 40 oranges is Rs .

(a). 620
(b) 660
(c) 820
(d) 780​

Answer 1

Solution 1

Let price of one apple = a

Price of one orange = b

Price of 80 apples = Price of 120 oranges⇒

80a = 120b

⇒2a = 3b

⇒b = 2a / 3 -------- (1)

Price of 60 apples + Price of 75 oranges = Rs. 1320

⇒60a + 75b = 1320

⇒4a + 5b = 88

⇒4a + 5 (2a)3 = 88 [∵ substituted value of b from (1)]

⇒12a + 10a = 88 × 3

⇒6a + 5a = 44 × 3

⇒11a = 44 × 3

⇒a = 4 × 3 = 12

b = 2a/3 = 2 × 12/3 = 8

Total price of 25 apples and 40 oranges

= 25a + 40b

= 25 × 12 + 40 × 8

= 300 + 320 = 620

Solution 2

80 apples ≡ 120 oranges

⇒2 apples ≡ 3 oranges

⇒60 apples ≡ 90 oranges

60 apples + 75 oranges = 1320

⇒90 oranges + 75 oranges = 1320

⇒165 oranges = 1320

⇒1 orange = 8

1 apple = 3 × 8/2 = 12

25 apples + 40 oranges

= 25 × 12 + 40 × 8 = 620