Friday 26 August 2011

DAY 357

On a 99 year lease, 2/3 of the time past equals 4/5 of the time remaining. How much time is left on the lease?

Answer:

45 years ......... Let x = time left - (99-x) = time past
2/3 (99-x) = 4/5 x


DAY 356

How many 5th Sundays are there in a year? (Ignore the possibility of 53 Sundays.)

Answer:
4 ......... There are 52 Sundays in a year. Each month has at least four, which is 48. The remaining 4 are fifth Sundays.

NOTE from JA: 
September 3, 2016 

I have been thinking about this problem for some time. The above statement about 48 Sundays is also true of every other day of the week. So 48 x 7 = 336. This leaves 29 more days (365-336). 29 divided by 7 = 4 remainder 1. This means there are 4 fifth Mondays, Tuesdays, Wednesdays, Thursdays, Fridays, and Saturdays - as well as 4 fifth Sundays. What about the extra day? It must mean that every year has one day that occurs 53 times - cycling through the week every seven years.

DAY 355

What do these rebus puzzles mean?

1. DECIMAL.
2. DECIMAL DECIMAL DEIMAL DECIMAL DECIMAL

Answers:

1. Terminating decimal (1/4 = .25)
2. Repeating decimal (1/3 = .33333.......)

Tuesday 23 August 2011

DAY 354

Ten students took a test with a maximum score of 100 points. The average of the ten scores was 92. What is the lowest score a student could have earned?

Answer:

20 ........ (9 x 100) + 20 = 920 ....... 920/10 = 92
DAY 353

A woman has 3 children, and the product of their ages is 17. Their ages are in whole numbers (no fractions or decimals). How old are the children?

Answer:
The oldest is seventeen and the twins are 1.
DAY 352

What a pair we are,
Our sum is 100;
Our product tells you more,
For it is our sum times 24.
Who are we?

Answer:

40 and 6o .......... X(100 - X) = 2400

Monday 22 August 2011

DAY 351

When could this equation be true?

1 + 1 + 1 = 1

Answer:

1 foot + 1 foot + 1 foot = 1 yard
DAY 350

When could this equation be true?

30 + 30 = 1

Answer:

It could be true if you are adding seconds to get 1 minute, or minutes to get 1 hour.
DAY 349

The area of a square is (x + y) squared. What is the perimeter of the square?

Answer:

4(x + y) .......... The area of a square is the side squared. So the side must be (x + y).

Saturday 6 August 2011

DAY 348

A horse walks a certain distance each day. On one day the horse's inside legs walked 30 miles, but its outside legs walked nearly 31 miles. How is this possible?

Answer:

The horse walks in a circle. The diameter of the circle is greater for the outside legs than for the inside ones. Therefore the circumference of the outside circle is greater.

Wednesday 3 August 2011

DAY 347

If you could count to 200 in 1 minute, and got 1 day off every 4 years (to account for leap years),
how long would it take you to count to 1 billion?

Answer:

9 years, 187 days, 5 hours, 20 minutes
DAY 346

1. What number is equal to 9 times the sum of its digits?
2. Write 8 using three nines.
3. Write 12 using six ones.

Answer:

1. 81
2. 9 - 9/9
3. 11 11/11