Proportions
Solve:
x/5 = 8/20
x = 2
What is 30% of 100?
30
What is the probability of rolling a 1 on a number cube?
Is the following event dependent or independent: flipping a coin and getting 3 heads in a row.
independent
What is the percent change from 10 to 15?
50% increase
Solve
4/12 = c/6
c = 2
16 is what percent of 32?
What is the probability of getting an even number when rolling a number cube?
1/2 or 50%
State whether the event is independent or dependent:
getting two red gumballs in a row from a gumball machine
dependent
What is the percent change from 200 to 150?
25% decrease (or -25%)
Solve
-9/m = 3/2
m = -6
What is 8% of 50?
2/3 or approx. 66.7%
When flipping three coins, what is the probability of getting three tails in a row?
1/8
What is the percent change if your salary used to be $60,000 and is now $75,000?
25% increase
Solve
12/r = 4/(0.5r - 1)
cross mult step:
4r = 12(0.5r-1)
distribution:
4r = 6r - 12
12 = 2r
r = 6
75 is what percent of 125?
60%
Events that are mutually exclusive opposites, such as being born a twin and not being a twin, are called ________ events.
complement
When rolling a number cube, what is the probability that you get a 2 followed by a 6?
1/36 or approx. 2.7%
(1/6) * (1/6)
In 1980, the median price of a single-family home in the US was $64,600. In the first quarter of 2023, the median price was $436,800. What is the percent change, rounded to the nearest whole percent?
576% increase
Solve
(d-2)/(d+9) = 3/14
d = 5
cross mult step:
3(d+9) = 14(d-2)
distribution step:
3d+27 = 14d-28
55=11d
d=5
9.3 is 14% of what? Round to the tenths.
66.4
A game requires you roll two dice and add together their results. What is the probability of getting a sum that is divisible by 3?
1/3
There are 36 total outcomes when rolling two dice.
3, 6, 9, and 12 are possible sums that are divisible by 3.
3 can occur two ways: (1, 2) and (2, 1)
6 can occur five ways: (1, 5), (2, 4), (3, 3), (4, 2), (5, 1)
9 can occur four ways: (3, 6), (4, 5), (5, 4), (6, 3)
12 can occur one way: (6, 6)
This totals 12 ways to get a number divisible by 36 out of 36 total possible outcomes. 12/36 = 1/3
You have 2 red marbles, 5 green marbles, and 3 purple marbles in a bag. What is P(purple then red) without replacing the marbles?
1/15 or approx. 6.7%
the event is dependent
(3/10)*(2/9)=6/90=1/15
The world record for the mile run in 1855 was 4 minutes and 28 seconds. The current world record is 3 minutes and 43 seconds. Find the percent change. Round to the nearest tenth of a percent.
(Hint: convert both times to seconds first.)
16.8% decrease