Lower Elementary
Question: Olivia bought four bags of chips that cost $1.50 each. If she buys three drinks for the same amount of money, how much does each drink cost?
Answer: $2.00
Note: The sodas each cost the same amount. The total for 4 bags of chips is (4 x $1.50) $6.00. Three drinks cost $6.00. The cost for one drink is $6.00 / 3 = $2.00.
Upper Elementary
Question: There are 36 cows on Mr. Gregory’s farm. 1/4 of the cows are brown. 5/12 of the cows are white with brown spots. The rest of the cows are black. How many black cows are there?
Answer: 12 black cows
Note: One way to find the number of black cows is to find the number of brown cows and the number of white cows with brown spots and subtract that from 36.
1/4 of 36 = 9 and 5/12 of 36 = 15. 15 + 9 = 24. 36 – 24 = 12.
Another method would be to find the fractional part of the cows that is black. Then find that fraction of 36.
1/4 + 5/12 + _____ = 1. 1/4 = 3/12 so 3/12 + 5/12 + _____ = 1. 8/12 + ______ = 1.
The fractional part of cow that is black is 4/12 or 1/3. 1/3 of 36 = 12.
Middle School
Question: Jake, Zack, and Mark have a total of $800. Jake has $340. The ratio of Zack’s money to Mark’s money is 3:2. How much money does Mark have?
Answer: $184
Note: First find out how much money Zack and Mark have combined by subtracting Jake’s money from the total. $800 – $340 = $460.
The ratio of Zack’s money to Mark’s money is 3:2. That means if you take the total amount ($460) and divide it into equal parts. Zack gets 3 parts and Mark gets 2 parts.
This gives a total of 5 parts in the whole. To find the value of each part divide $460 into 5 equal parts. $460 / 5 = $92.
Since each part is worth $92 and Mark gets 2 parts, the amount of money Mark has is ($92 x 2) = $184.
Algebra and Up
Question: The price of a DVD went from $20 to $16. If the same percent discount is applied to a video game, what is the new price of a video game that originally cost $30?
Answer: $24
Note: First find the percent discount of the DVD.
Percent of change = (change in price/original price) x 100
(20 – 16 / 20) x 100 = 4/20 x 100 = 1/5 x 100 = 20
or 1/5 x 100 = .2 x 100 = 20
The percent of change = 20% or 1/5
To find the amount of the discount on $30 find 20% of 30 or 1/5 of 30 = 6.
Finally subtract the amount of discount from the original price. $30 – $6 = $24
