Math
State the next number in the Fibonacci sequence.
1, 1, 2, 3, 5, 8, 13, ....
21
A baby has 300 bones, but an adult has 206. What happens to the "missing" bones?
They are fused.
Many of a baby's "bones" are actually flexible cartilage. Over time, a process called ossification replaces this cartilage with hard bone.
Multiple smaller bone pieces join to form a single, larger, stronger bone (for example, the several plates of a baby's skull fuse into one solid cranium).
If 5 machines can make 5 widgets in 5 minutes, how long would it take 100 machines to make 100 widgets?
5 min
Four students A, B, C, D each arrive at school at different times:
0700, 0710, 0720, 0730. Who arrives first?
* A arrives after B
* C arrives at 07 10
* D does not arrive first
B arrives first.
You have a 3 x 3 x 3 cube and paint the outside entirely red.
After sawing it into 27 smaller 1 x 1 x 1 cubes, how many of these small cubes have exactly zero red faces?
1
only the 1 smaller cube in the centre of the original cube is not painted.
What colour does a red shirt appear under a pure blue spotlight?
Black
A red shirt only reflects red light. Since a pure blue spotlight contains no red wavelengths, the shirt absorbs all the blue light and reflects nothing back to your eyes.
A drawer contains 10 red socks and 10 blue socks. If you reach blindly in the dark, what is the minimum number of socks you must grab to be 100% certain you have a matching pair?
3 socks
When the first 2 socks are red and blue, the 3rd one will definitely match any of them.
On a 12-hour digital clock (displaying hours and minutes), how many occurrences between 1:00 and 5:00 will all the digits on the clock add up to 3?
6 occurrences
1:02, 1:11, 1: 20, 2:01, 2:10, 3:00
A snail is at the bottom of a 30-foot well.
Each day it climbs up 3 feet, but it slides back 2 feet afterwards.
How many days will it take to reach the top?
A. 30 days B. 27 days C.28 days D.15 days
C. 28 days
In the first 27 days, the snail reaches 27 foot.
On the 28th day, once it reaches the top, it will not slide back.
If you were to take a standard compass to the Geographic North Pole, where would the needle point?
Downward/towards the ground
This happens because the Earth’s magnetic field lines are vertical at the poles. The "North" end of the magnetic needle is attracted to the magnetic pole inside the Earth, so it tries to dive straight down rather than pointing horizontally along the surface.
What is the smallest number that can be divided exactly by all numbers from 1 to 10?
A. 360 B. 504 C. 1260 D.2520
D.2520
2520 = 2^3 x 3^2 x 5 x 7, and it has factors 1, 2, 3, ..., 9, 10.
1260=2^2 x 3^2 x 5 x 7, and it cannot be divided by 8
504 =2^3 x 3^2 x 7, and it cannot be divided by 5
360 = 2^3 x 3^2 x 5, and it cannot be divided by 7
A clock shows 3:15.
What is the angle between the hour hand and the minute hand?
A: 3 degrees B: 7.5 degrees C: 15 degrees D: 22.5 degrees
B
Hour hand moves 30 degrees in an hour. It moves 7.5 degrees in 15 min
What is the total sum of all the angles inside an equilateral triangle and 1 of the exterior angles?
300 degrees
You mix cornstarch and water to make "Oobleck." If you dip your finger in slowly, it’s a liquid. But if you punch it as hard as you can, your fist bounces off like it’s a solid brick. What is this type of fluid called?
A non-Newtonian fluid.
The force of your punch causes the starch particles to lock together instantly. The harder you hit it, the more "solid" it becomes.
A car travels from Point A to Point B at 30 km/h.
It immediately turns around and travels from Point B back to Point A at 60 km/h.
What is the average speed for the entire round trip?
40 km/h
A to B takes twice the time from B to A.
Average speed = 2D / 3T = 2/3 * 60 = 40 km/h
You have 9 gold coins that look identical.
However, one coin is a counterfeit that weighs less than the others.
Using a simple balance scale, what is the minimum number of weighings needed to guarantee that the fake coin is found?
minimum 2 weighings;
Divide into 3 equal groups.
#1: Identify the group with the fake coin (lightest)
#2: Identify the fake coin from the group (lightest)
You have a standard circular pizza. You are allowed to make only 4 straight-line cuts with a knife, and you cannot move the pieces between cuts.
What is the maximum number of pieces you can create?
Hint: The pieces need not be equal in size.
11 pieces.
Intersect as many earlier cuts made and you will get 11 pieces.
Two identical twins are 13. One stays on Earth; the other travels to a distant star at nearly the speed of light and returns. When they reunite, the traveler is 15, but the twin on Earth is 30. Which twin is "correct" about how much time has actually passed?
Both of them
This is time dilation. According to Einstein’s Relativity, time is not absolute; it physically moves slower for objects traveling at high speeds. Both experiences of time are scientifically "real."
A particular country has coins of the following denominations: 1 cent, 2 cents, 5 cents, and 10 cents. Using the coins I have, I can pay EXACTLY any amount up to and including 20 cents.
What is the smallest number of coins I could have?
5 coins: 1, 2, 2, 5 and 10-cent coins needed
1, 2 pay 1, 2 and 3 cents
1, 2, 2 and 5 pay 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 cents
1, 2, 2, 5 and 10 pay 1, 2, 3, ..., 20 cents
A girl has as many brothers as sisters, but each brother has only half as many brothers as sisters.
How many brothers and sisters are there in the family?
3 brothers and 4 sisters.
b = s - 1 and 2(b-1) = s