Questions courtesy of www.mathopolis.com
'Oops! something went wrong.',
Two balls are drawn at random without replacement.
If the first ball drawn is green, what is the probability the second ball is yellow?
After the first ball is drawn and found to be green, there are now 6 marbles left in the bag, 5 of which are yellow.
So, P (The second ball is yellow given that the first ball is green) = 5/6
Billy pulls out two socks at random without replacement.
If the first sock drawn is black, what is the probability the second sock is also black and Billy has a pair?
After the first sock is pulled out and found to be black, there are now 10 socks left in the drawer, 5 of which are black.
So, P (The second sock is black given that the first sock is black) = 5/10 = 1/2
Eva pulls out a pen at random, replaces it in the bag, and then pulls out a second pen at random.
If the first pen is blue, what is the probability the second pen is red?
After the first pen is pulled out and found to be blue, it is replaced, therefore there are still 7 pens altogether in the bag, 3 of which are red.
So, P (The second pen is red) = 3/7, and it didn't matter what the color of the first pen was!
C = 5/9 (F 32)
What is the value of C when F = 77?
If a = 3, then what is the value of 7 + 5a?
If a is replaced by 3, then: * 5a = 5 3 = 15 7 + 5a = 7 + 15 = 22*
How many diamonds (in total) will there be in the next step of the pattern?
The number of diamonds follows the pattern 2, 5, 8, 11, etc. So the rule is that the number increases by 3 each time.
So the number of diamonds in the next step of the pattern must be 11 + 3 = 14.
[(12 + 8) (7 2) + 3] 4
First, work out the round brackets (parentheses):
12 + 8 = 20 7 2 = 5
Therefore, (12 + 8) (7 2) = 20 5 = 4
Next, if you add the 3, you get (12 + 8) (7 2) + 3 = 4 + 3 = 7
Now that we've worked out what's inside the square brackets, we multiply by 4 and we get:
The digit in the hundreds place is greater than or equal to 5, so the 3 is rounded up to 4.
So, 23,911.95 rounded to the nearest 1,000 is 24,000.
Calculate: 19 38.6 19 18.6
Remember the Distributive Law: a b a c = a (b c)
Our numbers are: a = 19, b = 38.6 and c = 18.6
So, 19 38.6 19 18.6 = 19 (38.6 18.6) = 19 20 = 380
For the number 9,437,196, what does the 7 mean?*
1 → Easy as a breeze
6 → Bafflingly difficult