JLAB Practice Math Part 1

Alma bought a laptop computer at a store that gave a 20 percent discount off its original price. The total amount she paid to teh cashier was p dollars, including an 8% sales tax on the discounted price. Which of the following represents the original price of the computer in terms of p?

• 0.88p

• (0.8)(1.08)p

Answer explanation

So if p is the total amount Alma paid to the cashier and x is the original price of the laptop, the equation reads as follows:

p = (1.08)(0.8)(x)

Now solve for x by dividing both sides by (1.08)(0.8).

p/(1.08)(0.8) = x

The correct answer is "D."

Tags

CCSS.HSA.CED.A.4

10(23+7)=100ℓ+100ℓ

What is the value of ℓ in the equation above?

• 3/2

• 6/4

• 3/4

• 5/8

Answer explanation

1. 10(23+7)=100ℓ+100ℓ

2. Add the two numbers in the parenthesis, 23+7 is 30.

3. Multiply 10 to 30, that gives 300. Add 100ℓ and 100ℓ

4. 300 = 200ℓ

5. Divide, ℓ= 300/200 or 3/2

Tags

CCSS.7.EE.B.4A

If line ℓ is translated up 5 units and right 7 units, then what is the slope of the new line?

Answer explanation

The context of the question says that the line on that graph is translated, or moved, up 5 units and right 7 units. This does not change the slope of the line, it changes its points but the slopes will be the same with the original line on the graph and the newly translated line.

At a primate reserve, the mean age of all the male primates is 15 years, and the mean age of all female primates is 19 years. Which of the following must be true about the mean age m of the combined group of male and female primates at the primate reserve?

• m = 17

• m > 17

• m < 17

• 15 < m < 19

Answer explanation

The mean of the males is lower than the mean of the females. If they are combined, the mean of males and females at the primate reserve would be in between the mean age of male primates (15) and the mean age of female primates (19). Essentially, you could also do 15 + 19 = 34 and divide it by 2 and you get 17 which would fit the expression, 15 < 17 < 19.

Tags

CCSS.6.SP.B.5C

In the figure above, △ABC is similar to △EDC, with ∠BAC corresponding to ∠CED and ∠ABC corresponding to ∠CDE. Which of the following must be true?

• A) AE is parallel to BD

• B) AE is perpendicular to BD

• C) AB is parallel to DE

• D) AB is perpendicular to DE

Answer explanation

You must use geometric logic to find the relationship. A is wrong because line AE is not parallel to line BD, they cross. B is wrong because line AE is not perpedicular to line BD, it crosses but they are not perpendicular, the two lines don't create two 90 degree angles. C is right because according to the converse of the alternate interior angle theorem, if ∠BAC corresponds to ∠CED they could be congruent so if thats true, lines AB and DE are parallel.

Tags

CCSS.HSG.SRT.A.2

How many of the 9 people have an actual height that differs by more than 3 centimeters from the height predicted by the line of best fit?

• A) 2

• B) 4

• C) 6

• D) 9

Answer explanation

There are 9 dots on the graph, those represent the 9 people. The question is asking you to compare each dot's y value to the line of best fit. Each line on the y axis is counting by ones so at x=4, the height of that person is 157 cm but on the line of best fit the height should be at around 161 cm, thats a difference of 4 cm. You can repeat these steps for the rest of the dots.

Tags

CCSS.HSS.ID.B.6B

• 2

• 4

• 9

• 10

Answer explanation

This question is quite easy, the context of the question is telling you to replace k with 3 in the equation. So, x-1/3 is equals to 3. Now, it's telling us to find the value of x so we want to isolate x. To do this we multiply 3 from the left side to 3 on the right side to get 9. Now we have x-1 = 9. Finally, to isolate x we must +1 on the left side to cancel it and add it to the right. X = 10

Tags

CCSS.7.EE.B.4A

• -1+12i

• -1-6i

• 15+12i

• 15-6i

Tags

CCSS.HSN.CN.A.2

Tags

CCSS.HSA.APR.A.1

• 3

• 5.7

• 9.5

• 14.3

Answer explanation

This question is quite easy, the question tells us the answer already. h is the height of the boy in inches. a is how many years the boy aged between the ages of 2 and 5. The constant 3 is the number of eaches the boy grows each year. 28.6 is his starting height.

Tags

CCSS.HSF.LE.B.5