A alone can do a work in $30 \mathrm{days}$. B alone can do the same work in $40 \mathrm{days}$. If they work on alternate days starting with A, then in how many days (correct up to two places of the decimal) the work will be completed?

Ten people can do a work in $30$ days. In how many days, can 15 people complete double the work - 

1.$40$

2. $25$

3. $20$

4. $45$ 

G is twice as fast as S in doing work. If G can do a work in $30$ days less than S, how many days will they take to complete the work together? 

1.$25$
2. $20$
3. $22$
4.$15$ 

X can do 5 times faster work than that of Y and so it takes 36 days less than Y. Find the time in which X alone can complete the work?