Mind Twister

Yesterday’s Math Problem:

A papaya tree was planted 2 years ago. It increases at the rate of 20% every year. If at present, the height of the tree is 540 cm, what was it when the tree was planted?

1] 432 cm

2] 324 cm

3] 375 cm

4] 400 cm

Answer:

3] 375 cm

Solution: Take .20 if 375 which equals 75. By the end of the first year, the tree was 450 cm high. Now take .20 of 450 which equals 90. Add 90 to9 450 and you have 540 – the height of the tree now.

Today’s Mind Twister:

Five racing drivers, Alan, Bob, Chris, Don, and Eugene, enter into a contest that consists of 6 races. The results of all six races are listed below:

  1. Bob always finishes ahead of Chris.
  2. Alan finishes either first or last.
  3. Eugene finishes either first or last.
  4. There are no ties in any race.
  5. Every driver finishes each race.
  6. In each race, two points are awarded for a fifth place finish, four points for fourth, six points for third, eight points for second, and ten points for first.

If Frank enters the third race and finishes behind Chris and Don, which of the following must be true of that race?

1] Eugene finishes first.

2] Alan finishes sixth.

3] Don finishes second.

4] Frank finishes fifth.

5] Chris finishes third.

How Many Cars?

Last number sequence challenge:

What is the missing number in the following sequence of numbers?

1, 5, 14, 30, ?, 91

1] 45

2] 55

3] 60

4] 70

5] None of these

Answer:

2] 55.

Why? You start with 1 which is incremented by the square of 2 or 4 which equals 5. The next number in the sequence is 5 plus the square of 3 (which is 9), which equals 14. The number to square at 30 is 5, so 30+25 (the square of 5) = 55.

Today’s Problem:

There are 3 societies A, B, C. A lent cars to B and C as many as they had already. After some time B gave as many tractors to A and C as many as they have. After sometime C did the same thing. At the end of this transaction each one of them had 24. Find the cars each originally had.

1] A had 21 cars, B had 39 cars and C had 12 cars

2] A had 39 cars, B had 39 cars and C had 12 cars

3] A had 39 cars, B had 21 cars and C had 19 cars

4] A had 39 cars, B had 21 cars and C had 12 cars