Question

20 kg of potato cost as much as 30 kg of onion, 15 kg of onion cost as much as 18 kg of cabbage. If 10 kg of cabbage cost Rs. 50 find the cost of 24 kg of potato.
A). Rs. 216
B). Rs. 72
C). Rs. 108
D). Rs. 96

Answer 1

Hint: In the given question, we have been given the relation between several different entities or items. The relation is between their prices with their weights given. Then we have been given the price of one entity in terms of its weight. We have to calculate the price of another entity using the given relations. We are going to solve it by taking it backwards – we are first going to use the given price to find the price of the item given with its relation and continue going back until we get the price of the required amount and then multiply the given number of weights to be calculated to get the answer.

Complete step by step solution:
Given, the price of \[10kg\] cabbage is \[Rs50\].
So, the price of \[1kg\] cabbage is \[Rs5\].
Now, the cost of \[18kg\] cabbage and \[15kg\] onion is the same.
Cost of \[18kg\] cabbage \[ = 5 \times 18 = Rs90\].
So, the price of \[15kg\] onion is \[Rs90\].
Cost of \[30kg\] onion is \[2 \times 90 = Rs180\].
Now, the cost of \[30kg\] onion and \[20kg\] potatoes is the same.
So, the cost of \[20kg\] potato is \[Rs180\].
Cost of \[1kg\] potato is \[Rs9\].
Hence, the cost of \[24kg\] potato is \[9 \times 24\] or \[Rs216\].
Thus, the correct option is A.

Note: In this question, we had to calculate the price of a given number of parameters of one item, with the price of that item given in terms of other items. We did it by taking the procedure backwards - we first used the given price to find the price of the item given with its relation and continued going back until we got the price of the required amount and then multiplied the given number of weights to be calculated to get the answer.