Aapki demands ab hongi poori

Differentiate between decrease in demand and contraction in demand (decrease in quantity demanded).

A villager went to a hotel in a town with his big family, They consumed 23 idlis, 18 pooris, 7 dosas and 19 vadas. The bill came to them was Rs 108. On next day, they consumed 34 idlis, 8 vadas, 22 pooris and 7 dosas. The bill came to them was Rs 114. If one ili costs the same as one vada then what is the cost of one poori?