For the following questions answer them individually
In one hour, a boat goes 11 km along the stream or 5 km against the stream. Find the speed of the boat in still water.
From the points 'x' m and 'y' m away from the foot of a tree on either side of it the angles of elevation of the tree-top are $$Â \alpha , \beta $$ respectively. If $$ \alpha +Â \beta = 90^\circ $$, then find the height of the tree.
Two vehicles start from places P and Q towards Q and P respectively at the same time. After crossing each other, they complete their journey in 7/2 hours and 18/7 hours respectively. If the second vehicle moves at a speed of 70 km/h, then find the speed of the first vehicle.
What is the distance between two consecutive compressions or two consecutive rarefactions called?
In a certain code, 'ABC DEF' is written as 'ZYX WVU'. How would 'FAIL' be written in that code?
The Simple Interest for first 2 years is 6%, next 2 years is 7% and for any number of years exceeding 4 years is 8%. Find the total interest on a principal 'P' at the end of 7 years.
