Question

aladdin has 12 gold coins in his magic bag. genie tells him that for every 100 gold coins he has in his magic bag, he will get 25 extra gold coin every year. How many years later will aladdin have 21 gold coins in his bag?

Answer 1

In 3 years.

Explanation:

For every 100 gold coins Aladdin has in his magic bag, he will get 25 extra gold coin every year.

This means that for every
`100/ 25=4` gold coins Aladdin will get
`25/ 25=1` extra gold coin every year.

Aladdin has 12 gold coins in his magic bag. Then after first year, he will get
`12/ 4=3` extra gold coins this year. In total he will have
`12+3=15` gold coins.

Aladdin has 15 gold coins in his magic bag. Then after second year, he will get
`15/ 4=3\ (remainder \ 3)` extra gold coins this year. In total he will have
`15+3=18` gold coins.

Aladdin has 18 gold coins in his magic bag. Then after third year, he will get
`18/ 4=4\ (remainder \ 2)` extra gold coins this year. In total he will have
`18+4=22>21` gold coins.

Hence, in three years, Aladdin will have 21 gold coins.