Directions:Study the following table carefully to answer these questions:

Percentage of Marks obtained by six students in six subjects

What is the ratio between total marks obtained by D in Biology, Maths and English together and the total marks obtained by F in these subjects together respectively?

Two mobile phones were purchased at the same price. One was sold at a profit of 30 % and the second was sold at a price which was Rs 2500 less than the price at which the first was sold. If the overall profit earned by selling both the mobile phones was 5 %, what was the cost price of one mobile phone? 

If a chair sold for Rs. 600 at the profit of 20%, then the original price of the chair is:

Mr. Khanna took a loan of Rs 10,000 on simple interest for two years at the rate 3% per annum. The total amount that he will be paying as interest in 2 year is 3% of his monthly salary. What his monthly salary?

Four runners started running simultaneously from a point on a circular track. They took 200 seconds, 300 seconds, 360 seconds and 450 seconds to complete one round. After how much time do they meet at the starting point for the first time? 

A goldsmith observes that one of his employees prepares a necklace in 9 hours, while another employee prepares it in 10 hours. If they work together, they stud 10 gems less every hour and thus prepare a necklace in 5 hours, then the number of gems studded in each necklace is: