Puzzle with Numbers – Total to 100

August 3, 2016


The digits 1 to 9 are written in ascending order. Without changing the order of the digits and using only the + and – signs three times and four times make the total to 100. The figure shows an example of using + and – six times.   Solution to Total to 100 Source: Puzzles […]

Posted in: Mental Math, Puzzles

Train Problem – Relative Velocity

March 29, 2016


Two trains, each 400 m long, pass each other completely in 10 secs when they are moving in opposite directions. When they are moving in same direction, the trains take 20 secs to pass each other completely. Find the speed of both trains? Click for other Train Problems Click for solution to Train Problem

Find the Probability

March 19, 2016


A and B throw a dice alternatively. A wins if he throws a number greater then 4. B wins if he throws a number > 4. What is the probability of B winning if starts first? Click for solution to Probability of B Winning

Trigonometric Translations

March 18, 2016


Consider the equations y = a sin(bx+c) + d where a, b, c and d are constants Each of these constants has a different impact on the original sine function 1) constant a – Value of “a” indicates the amplitude of the sine function. If a > 1, amplitude increase by the factor of “a” […]

Happy π Day

March 14, 2016


Earlier posts on pi Happy Pi Day

Posted in: Doodle, Puzzles

Conditional Probability

March 11, 2016


Two numbers are selected at random from the integers 1 to 9. If the sum of the two numbers is even, find the probability that both numbers are odd? Click for solution to Conditional Probability

Linear Equations – Line of Symmetry

March 6, 2016


Find the line of symmetry for the figure ABCDE given below                 Hint: See Equations for different forms of line Click for solution to Line of Symmetry