Riddles 1 [With Answers]

Puzzle 1: What are the next two letters in the following series and why?

W A T N T L I T F S _ _

Solution: The letters are the first letters of the words in the question. Thus, the next two letters are A and W.

Puzzle 2: Solve it?

2 + 3 = 8,

3 + 7 = 27,

4 + 5 = 32,

5 + 8 = 60,

6 + 7 = 72,

7 + 8 =??

Solution: 98

2 + 3 = 2 * [3 + (2-1)] = 8

3 + 7 = 3 * [7 + (3-1)] = 27

4 + 5 = 4 * [5 + (4-1)] = 32

5 + 8 = 5 * [8 + (5-1)] = 60

6 + 7 = 6 * [7 + (6-1)] = 72

Therefore

7 + 8 = 7 * [8 + (7 - 1)] = 98

x + y = x[y + (x - 1)] = x^2 + xy - x"

Puzzle 3: How can you make the following equation true by drawing only one straight line?

5 + 5 + 5 = 550?

Solution: Draw a line on the first plus sign. This turns it into a 4! The equation then becomes true: 545 + 5 = 550.

Puzzle 4: What are the next three numbers in this series?

4, 6, 12, 18, 30, 42, 60, 72, 102, 108, ?, ?, ?

Solution: The series lists numbers that are flanked by two prime numbers.

4 (3 and 5 are prime)

6 (5 and 7 are prime)

12 (11 and 13 are prime)

18 (17 and 19 are prime)

30 (29 and 31 are prime)

42 (41 and 43 are prime)

60 (59 and 61 are prime)

72 (71 and 73 are prime)

102 (101 and 103 are prime)

108 (107 and 109 are prime)

Thus, 138 (137 and 139 are prime), 150 (149 and 151 are prime), 180 (179 and 181 are prime).

Puzzle 5: Can you add eight 8's together so they add up to an even one thousand?

Solution: 888 + 88 + 8 + 8 + 8 = 1000