If $\log_2 x + \log_4 x = 5$, what is the value of $x$?
A boat travels 36 km downstream in 3 hours and 24 km upstream in 3 hours. What is the speed of the boat in still water?
If $x^2 - 5x + 6 = 0$, what is the value of $x^3 - 3x^2 + 2x$?
The cost price of an article is Rs. 200. It is sold at a 10% discount on the marked price, yielding a 25% profit. What is the marked price?
If $a, b, c$ are in geometric progression and $a + b + c = 21$, $abc = 216$, what is the value of $b$?