121. What number best fits in the following sequence:

18, 14, 12, 11, ?, 10.25

10.5. You divide the number shown by 2 & then add 5 for each step in the sequence.

122. A man went into a bank with exactly $1000, all in dollar bills. He gave
the money to a cashier and said, "Put this money into ten bags in such a way that if I call and ask for a certain number of dollars, you can hand me one
or more bags, giving me the exact amount called for, without having to open any of the bags." How was the cashier able to do this?

The contents of the ten bags should be $1, $2, $4, $8, $16, $32, $64, $128, $256 and $489.

123. What is the missing number in the sequence below?

361,117 360,204
359,291 358,378
357,465 ?

356,552. Each succeeding number is 913 less than its predecessor.

124. A census taker asked a housewife how many people lived in her house and what
their ages were. The woman told him that three daughters lived in the house, that the product of their ages was 36, and that the sum of their ages was
the number of the house next door. The census taker went next door and looked at the number on the door. When he came back, he told the housewife
that the information she had given was insufficient, whereupon she replied, "My oldest daughter is sleeping upstairs." The census taker
thanked her and promptly figured out the daughters' ages. What were they and how did he know?

The woman had a 9-year-old daughter and 2-year-old twins. Since the census taker knew both the product and the sum of their ages, confusion could only arise if two or more sets of ages led to the same product and sum. Breaking 36 into three factors, only two sets of ages (9,2,2, and 6,6,1) lead to the same sum of 13. The woman's final piece of information told the census taker that there was only one oldest daughter, not two.

125. Find the six-digit number in which the first digit is one more than the
second; the second is one more than the third; the fourth is one less than the third; and the fifth and sixth are the sum of the first and second and...no
digit appears more than once.

126. Peter Piper picked a peck of pickled peppers, but how long did it take
him? Peter and his friend Paul, working together, could pick a peck in 20 minutes; Paul and his friend Percival, working together, could do the job in 30
minutes. Peter and Percival working together, though, would take 40 minutes to pick a peck. So, how long would it take for Peter to pick a
peck of pickled peppers by himself?

Peter can pick a peck in 48 minutes.

127. If a bouquet of six tulips and eight daisies costs $10, but a bouquet of eight tulips and six daisies costs $11, how much does each flower cost?

Each tulip cost $1; each daisy costs 50¢.

128. Two railway trains, one 400 feet long and the other 200 feet long, ran on
parallel tracks. It was found that when they went in opposite directions, they passed each other if five seconds, but when they ran in the same direction,
the faster train would pass the other in fifteen seconds. A curious passenger worked out the speed of each train from these facts. This, of
course, assumes that both trains run at constant speeds. Can you work out the trains' speeds?

In 5 seconds, both trains (together) go 600 feet, or 120 feet per second. In 15 seconds, the faster train gains 600 feet, or 40 feet per second. Add together the sum and difference of the rates obtained, and divide by 2. This gives 80 feet per second as the speed of the faster train (roughly 54-1/2 miles per hour), from which it is clear that 40 feet per second is the speed of the slower train (roughly 27-1/3 miles per hour).

129. In the farmyard are a number of sheep and hens. There are twice as many hens as sheep, and if you add the total number of heads between them to the total number of legs, you get 187. How many are there of each animal?

130. AB + CD + (EF/GH) + (I/J) = 100

Each of the ten digits, from 0 to 9 has been used once and only once in the construction of the above sum. Can you replace the letters with the digits? There is more than one valid answer!

Here are two solutions: 17 + 82 + (45/90) + (3/6) = 100 & 49 + 50 + (38/76) + (1/2) = 100.