If a^1/2 + b^1/2 - c^1/2= 0 find (a+b-c)^2

In a school 2/3 of the students study a language of those who study a language 2/5 study french

If there is 20 dogs in the shelter and 5 dogs get homes, and then 43 more dogs come. how many dogs are there in the shelter?

When george started his current job, his employer told him that at the end of the first year, he would receive two vacation days. after each year worked, his number of vacation days will double up to five work weeks (25days) of payed vacation. how many vacation days will he have in 4 years