SAT Math - How to multiply integers

A paint crew can paint walls in hours. At this rate, how many walls can the paint crew paint in hours?

Explanation

First, divide by to determine how many walls the paint crew can paint in hour.

$\frac{45}{15}=\frac{15\cdot 3}{15}=3$

divided by is equal to .

Then, multiply this number by hours.

$8\cdot 3=24$

Calculate in the following series:

Explanation

Each element is obtained from the previous one by alternating the following operations: multiplying by 5 and adding 6.

$\begin{matrix} 10+6 = 16\ 16 \times 5 = 80 \ 80+6 = 86 \; ; 86 \times 5 = 430 \ ; ; 430+6 = 436\ ; ; 436 \times 5 = 2180 \end{matrix}$

If we let be the first element, then

$A \times 5 = 10$

Solve for :

$A \times 5 \div 5 = 10 \div 5$

Janet can pick between 10 and 20 tomatoes in an hour. What is a possible amount of time for Janet to pick 120 tomatoes?

$6\text{ hours}$

$20\text{ hours}$

$5\text{ hours}$

$16\text{ hours}$

$4\text{ hours}$

Explanation

Since Janet can pick between 10 and 20 tomatoes in an hour, there is a range for which she can pick 120 tomatoes. Therefore, to find the possible amount of time it will take Janet to pick 120 tomatoes set up two fractions.

$\text{Time}_1=\frac{\text{Total Tomatoes Picked}}{\text{Rate}_1}$

The first fraction will use the rate of 10 tomatoes an hour.

Therefore, identifying the variables are as follows.

$\\text{Total Tomatoes}=120 \\text{Rate}_1=10$

Substituting these into the fraction results in a possible time

$\text{Time}_1=\frac{120}{10}=\frac{12\times 10}{10}=12\text{ hours}$

The second fraction will use the rate of 20 tomatoes an hour.

$\text{Time}_2=\frac{\text{Total Tomatoes Picked}}{\text{Rate}_2}$

Therefore, identifying the variables are as follows.

$\\text{Total Tomatoes}=120 \\text{Rate}_2=20$

Substituting these into the fraction results in a possible time

$\text{Time}_1=\frac{120}{20}=\frac{6\times 20}{20}=6\text{ hours}$

Of the answer selections 6 hours would be the correct answer.

An office wants to buy 22 computers at $900 each. The budget is $20,000 and the tax on computers is 9%. How many computers can the office afford?

Explanation

The office can only afford 20 computers.

1.09 * 900 = $981 is the actual price of each computer, with tax.

Divide:

20,000/981 = 20.39

Since the office cannot purchase a partial computer, we round down to 20 computers.

$F=ma$ in physics where $Force=mass\times acceleration$ .

If the mass is increased by 3 three times the original and the acceleration is increased by 7 times the original, how many times greater is the new force than the original force?

$21$