17. Two marks exercise problems VIII

1. It takes $60$ days for $10$ machines to dig a hole. Assuming that all machines work at the same speed, how long will it take $30$ machines to dig the same hole?

 

Number of days $=$

 

2. Forty students say in a hostel. They had food stock for $30$ days. If the students are doubled then for how many days the stock will last?

 

Number of days $=$