BrainBashers - Mathematical Puzzles

Puzzle 21

Last week I decided to cycle to my Grandparents's house.

On the 1^st day, I cycled half of the distance.

On the 2^nd day, I cycled one half of the remaining distance.

On the 3^rd day, I cycled three quarters of the remaining distance.

On the 4^th day, I cycled 10 miles.

On the 5^th day, I cycled two thirds of the remaining distance.

On the final day, I cycled the remaining 5 miles.

How far is it to my Grandparent's house?

workings hint answer print

www.brainbashers.com /puzzle/zewf share

Puzzle 22

How many squares of any size on this chessboard do not contain a rook?

Rooks On C3, C6, F3, F6

workings hint answer print

www.brainbashers.com /puzzle/zxqo share

Puzzle 23

If …

   ⁷/₂₈ of 64 is 16,

   and ⁹/₁₂ of 100 is 75,

   and ³/₉ of 33 is 11,

what is ⁵/₁₅ of 45?

workings hint answer print

www.brainbashers.com /puzzle/zytt share

Puzzle 24

Can you highlight exactly three numbers that add to 17?

3x3 Grid: 2 4 1, 1 3 8, 9 2 1

Note: this puzzle is not interactive, and the numbers cannot be clicked.

workings hint answer print