In a street, there are certain number of houses. People in that street are decided to paint their houses with certain colours. If four houses are painted with each colour, then one house will be left without any colour. If five houses are painted with each colour, then one colour will remain. Find the number of houses in that street ?

Correct Answer: 25

Let x be number of houses and y be colors.

on the basis of question x = 4y+1x = 5(y-1)on solving these 2 equations x = 25