Word Problems Flashcards
What is the equation to calculate total cost?
Total cost = unit price x quantity purchased
What is the equation for profit?
Profit = revenue x cost
What is the equation for total earnings?
Total earnings = wage rate x hours worked
What is the equation for miles when you have the miles per hour and the time?
Miles = miles per hour x hours
What is the process of the working backwards strategy?
Plug the answers into a problem to see which makes the math work.
Which answer choices do you choose to work backwards from?
1) When numerical answer choices
2) “Nice” answer choices - small or with 0s at the end
3) When the question asks for a definite number, like a total or a single variable
When do you not use working backwards strategy?
When the question is asking for a combination of variables (eg. the difference between Person A and Person B)
What is a relative rate?
When two bodies are traveling at the same time
If the object spends more time traveling at a slower rate, the average will always be closer to the ___ of the two rates than to the __.
If the object spends more time traveling at a slower rate, the average will always be closer to the slower of the two rates than to the faster.
What is the equation of speed?
Speed = total distance / total time
When 2+ workers are performing the same task, their rates can be ___ together.
Their rates can be added together.
If one worker is undoing the work of the other, ___ the rates.
Subtract the rates if one worker is undoing the work of the others.
When work involves completing a task, treat completing the task as ___ unit.
Treat completing a task as one unit of work.
When you know the rate of every worker, __ the rates of workers who work together to complete the same task.
Add the the rates if the workers are completing a task together.
When would you choose smart numbers?
To replace variables in questions where they are asking for relationships between variables. Especially used in questions where variables are used throughout, including the answer choices.
How do you choose a smart number?
1) Pick numbers with different characteristics (even vs. odd)
2) Follow constraints of the problem (eg. distance is not negative)
3) Choose numbers that work in the problem
You can/cannot replace variables in answer choices wtih smart numbers.
You can do this.
Smart numbers are used in questions with variables, but can also be used in __.
Can be used in questions asking for percentages or fractions, and in hard questions.
What types of smart numbers should you avoid choosing?
- Numbers where you may get the same numerical answers at different points in the problem
- 0 or 1 or a number used elsewhere in the problem
For percentages, which smart number should you use?
Use 100 if possible, unless it appears elsewhere in the problem.