Question

If one score oranges cost Rs. 45, how many oranges can be bought for Rs. 72? (1 score=20).

Answer 1

Hint: Using the points that a score of oranges contains 20 oranges and the cost of each score of orange is Rs. 45, find the cost of each orange. After that divide Rs. 72 by the cost of each orange to get the number of oranges that can be bought for Rs. 72. The method is called the unitary method.

Complete step-by-step solution -
It is given that the cost of one score of orange is Rs. 45. We know that 1 score of orange actually refers to 20 oranges. So, we can say that the cost of 20 oranges is Rs. 45.
Now let the cost of one orange be Rs. x. Therefore, we can say that:
$20x=45$
$\Rightarrow x=\dfrac{45}{20}=\dfrac{9}{4}$
So, the cost of one orange is Rs. $\dfrac{9}{4}$ .
Now, we will divide Rs. 72 by the cost of each orange to get the number of oranges that can be bought for Rs. 72.
$\therefore \text{Number of oranges=}\dfrac{72}{x}=\dfrac{\dfrac{72}{1}}{\dfrac{9}{4}}=\dfrac{72\times 4}{9}=32$
So, we can buy 32 oranges for Rs. 72, provided that the cost one score oranges is Rs. 45.

Note: Be careful with the signs and calculations as in such questions, the possibility of making a mistake is either of the sign or a calculation error. It is also important that you know the number of objects contained in one Dozen is twelve, in one score is 20 and other number related quantities for a given object.