161. Jim and Barbara bought four presents for various weddings, but they couldn't
agree on four identical gifts. They bought four separate gifts. The first cost $5.00 more than the second. The second was half the cost of the
first, plus one-third the cost of the first. The third cost two-thirds of the first, and the last one cost double the third. They spent a total of
$115. What did each of the gifts cost?

The presents cost $30, $25, $20, and $40.

162. If you reverse the digits of Rachel's age, you will have the age of her
grandmother. Her grandmother's age is also the sum of the two digits of Rachel's age squared. What are their ages?

Rachel is 18; her grandmother is 81.

163. A traveler in the desert, meeting three nomads about to consume some camel's
milk, asks whether they would share it with him for a price. They agree and pool the milk, the first contributing one pint more than the second, and the
second contributing one pint more than the third. They share the milk equally. On leaving, the traveler gives them a sum of money. After
some calculation, they decide that the first nomad should equitably get twice as much money as the second nomad. How much should the third nomad get?

The nomads contributed 5, 4, and 3 pints. Sharing the 12 among four people gives each of them 3 pints. The third nomad therefore drank his entire contribution, and so should not get paid anything.

164. What number is one-fourth of one-half of one-tenth of 16 multiplied by 20?

4. 16 x 20 = 320, 1/10 of 320 = 32, 1/2 of 32 = 16, 1/4 of 16 = 4.

165. One-third of an hour after a candle was lit, the other end was also
lit. It took a further one-third of an hour for the candle to burn out. If the candle was lit at both ends at the start, and one end was
quenched when only the middle one-third of the candle remained, how long in all would it take to burn the candle out?

The second method is really the first way backwards!! It, too, would take 2/3 of an hour to burn the candle out.

166. Using only four numerals and any mathematical symbols you choose, can you produce an equation that will yield the number 300?

167. What is the next number in this series?

21, 20, 18, 15, 11, ________?

6. Each step subtracts one more than the previous step.

168. If Timmy's toy soldiers are set up in rows of 3 across, one is left over; in
rows of 4, 2 are left over; in rows of 5, 3 are left over; and in rows of 6, 4 are left over. What's the least number of toy soldiers Timmy could have?

169. If you only have a 4-minute hourglass and a 7-minute hourglass, how do you measure 9 minutes?

Start both hourglasses. When the 4-minute hourglass runs out, turn it over (4 minutes have elapsed). When the 7-minute hourglass runs out, turn it over (7 minutes have elapsed). When the 4-minute glass runs out this time (8 minutes have elapsed), the 7-minute glass has been running for 1 minute. Turn it over once again. When it stops, 9 minutes have elapsed.

170. Jerry went out to the hardware store to buy some needed supplies. He
spent half of what he had plus $2.00 in the first store; half of what he had left plus $1.00 in the second store; half of what he had left plus $1.00 in the
third store; and in the last store, half of all he had. Three dollars were left over. How much money did he start with?

$64.00. (64 ÷ 2 = 32 + 2 = 34, now 30 left; ÷ 2 = 15 + 1, now 14 left; ÷ 2 = 7 + 1, now 6 left; ÷ 2 = 3).