Fast mixed tests, similar in format to the CCAT, include word problems with no calculator and about 20 seconds a question. The arithmetic is small on purpose. What costs time is setting the problem up.
Read the question last line first, so you know what you're solving for. Then reduce the story to one line:
- Speed: find the rate for one hour first, then scale it.
- Shared work: add the parts of the job each person does in an hour.
- Discounts one after another: apply the second to the sale price, never add them.
- Ratios: add the parts, find one part, then multiply.
- Ages: try the options. Test each one against both sentences.
Every wrong option is the answer a common slip gives, so a number that matches an option isn't proof you're right.