A student obtained total marks in Physics, Chemistry, Mathematics and English together is 150 more than the marks obtained by him in Physics and chemistry. What is the average marks obtained by him in Mathematics and English?

Jay rows a boat 216 km upstream and rows same distance downstream in a total of 30 hrs without any break. The speed in downstream is 20% more than the speed of boat in still water and the speed in upstream is 66.67% of the downstream speeD.  What is the speed of boat in still water?

The principal that yields a compound interest of Rs. 810 during the second year at 8% per annum is –

Water contains  of hydrogen and the rest is oxygen in 350g of water, oxygen will be?

The number that is to be added to 20% of 420 to have the sum as 40% of 240 is

A’s salary is 30% more than B’s salary. B’s salary is 25% less than C’s salary. C’s salary is 3/5 of D’s salary. What % of A’s salary is D’s salary?

Mr. Shyam wants to purchase a cooler costing Rs 6300. The tax is 5%. He requested the dealer to reduce the price to such an extent that he has to pay only Rs 6300 (inclusive tax). What will be the reduction needed in the price of cooler?

Ram is 3 times older than his brother. Then after how many years their age ratio will be 3:4?

A sum of money at compound interest amounts to Rs.815 in 3 years and Rs.854 in 4 years. What is the sum of money?