Question
A boat takes 7 hours to cover 294 km upstream and 9
hours to cover 486 km downstream. Find the time taken by the boat to cover 720 km upstream and 616 km downstream if speed of boat in still water is increased by 4 km/h and speed of stream is decreased by 2 km/h.Solution
Upstream speed = 294/7 = 42 km/h Downstream speed = 486/9 = 54 km/h Speed of boat in still water = (42 + 54)/2 = 48 km/h Speed of stream = (54 – 42)/2 = 6 km/h Increased speed of boat in still water = 48 + 4 = 52 km/h Decreased speed of stream = 6 – 2 = 4 km/h Required time taken = 720/(52 – 4) + 616/(52 + 4) = 15 + 11 = 26 hours
The value of the expression (1 + sec22° + cot68°)(1 – cosec22° + tan68°) is
If x + y + z = 19, xyz = 216 and xy + yz + 2x = 114, then the value of √ x3 + y3 + z3 + xyz is :
Solve the equation:
3(x − 2) + 4(2x + 1) = 5(2x − 3) + 7
Quantity I – In how many ways letters of MOBILE can be arranged when vowels are always together.
Quantity II – In how many ways let...
The expression of (cot θ + cosec θ −1) / (cot θ − cosec θ+1) is equal to
If (a + b)/c = 6/5 and (b + c)/a = 9/2, then what is the value of (a + c)/b?
Find x, given 5 (√5)x+6 = (√5)2x+7 :
If X = (√5 + 1) / (√5 – 1) and y = (√5 – 1) / (√5 + 1) then the value of (x 2+xy+y ...
10 women and 12 men complete a certain piece of work in 30 days, if each women takes thrice the time taken by a man to finish the work.
Quanti...
 is equal to:
Relevant for Exams:
