Area, time, work and labour, time and distance

There are 100 students in a hostel. Food provision for them is for 20 days. How long will these provisions last, if 25 more students join the group ?

The perimeter of a circle is equal to the perimeter of a rectangle whose length and breadth are respectively 14 centimetre and 8 centimetre. The area of the circle will be

The sides of a triangular plot are in the ratio of 3 : 5 : 7 and its perimeter is 300 m. The area of the triangular plot will be

12 men and 20 women can do a construction work in 6 days. The ratio of work force of men to women is 5 : 4. Which of the following option is wrong to complete the same work in 3 days ?