A certain sum becomes Rs 840 in 3 years and Rs 1200 in 7 years at simple interest. What is the value (in Rs) of principal? 

20 men could complete a work in 80 days. They worked together for 60 days, after that due to bad whether the work is stopped for 10 days. How many more men should be employed so as to complete the work in time?

There are 3 green, 4 orange and 5 white color bulbs in a bag. If a bulb is picked at random, what is the probability of having either a green or a white bulb?

Direction: Study the double bar graph given below and answer the questions.

The ratio of the participants in exhibition of class IX with the total participants of class IX is:

Directions: Given table shows the data of population in 5 different parks. Study the data carefully and answer the questions.

If 20% of total population did not visit on a particular day in park A of which male population was 60% then what percent of total population in park B is male population who visited in park A?

To travel 432 km, an Express train takes 1 hour more than Duronto. If however, the speed of the Express train is increased by 50%, it takes 2 hours less than Duronto. What is the speed (in km / hr) of Duronto train? 

The average weight of 14 children is 22 kg. If the weight of the teacher is also included, then the average weight becomes 23 kg. What is the teacher's weight?