There is a ring road connecting points A, B, C and D. The road is in a complete circular form but having several approach roads leading to the centre. Exactly in the centre of the ring road there is a tree which is 20 km from point A on the circular road. You have taken around the circular road starting from point A and finishing at the same point after touching the other three points. You then drive 20 km interior towards the tree from point A and from there reach somewhere in between B and C on the ring road. How much distance do you have to travel from the tree to reach the point between points B and C on the ring road?
The difference between a two-digit number and the number obtained by interchanging the digits is 36. What is the difference between the sum and the difference of the digits of the number if the ratio between the digits of the number is 1 : 2 ?
frank
"The study of mathematics, like the Nile, begins in minuteness but ends in magnificence"