Book Maths Puzzle

There is a point in a circle. What is the probability that this point is closer to its circumference than to the centre?

Read Solution (Total 1)

let radius be R
draw new circle inside the old one with same center O and radius
r = R/2
area of the bigger circle = pi*R^2= a1
area of the smaller circle = (pi*R^2)/4= a2
probability = a1-a2/a1= 0.75
11 years agoHelpfull: Yes(0) No(0)

Book Other Question

A man covered a certain distance at some speed. If he had moved 3 kmph faster, he would have taken 40 minutes less. If he had moved 2 kmph slower, he would have taken 40 minutes more. What is the the distance in km? Three boys P,Q and R are to speak at a function along with 5 others. If all of them speak in random order, what is the probability that P speaks before Q and Q speaks before R?