SAT word problems: writing the equation is the whole question
You solved it correctly. You just solved the wrong equation — and the wrong equation was written in the first ten seconds, before you did any work worth checking.
Why it happens
English orders words by emphasis; algebra orders them by operation. "Five more than twice a number" and "twice a number more than five" read almost identically and are different expressions. Once the equation is wrong, every step after it is correct and useless.
See the trap
A plumber charges $90 for the visit plus $45 an hour. Write the cost for h hours.
C = 90h + 45 — the first number met becomes the rate.
C = 45h + 90. The rate is the amount that repeats; the flat fee is paid once.
How to actually fix it
- 1Name the variable in words first: "h = hours worked", not just "let h be h".
- 2Ask which quantity repeats. That one multiplies the variable; the one paid once is added.
- 3Test your equation on a number you can check in your head — one hour here should give $135.
Practice this trap · 14 real questions
Each of these is a question from the free bank that turns on the mistake above — the trap is the reason its wrong answer looks right. Easiest first.
Showing 8 of 14. Keep going in Algebra →
FAQ
Is there a reliable order to read the sentence in?
Read for the relationship before the numbers. Find what depends on what, write that skeleton, and only then fill the numbers in. Reading left to right and writing symbols as you meet them is what produces the inverted setup.
How do I stop repeating this mistake?
Reading the explanation isn't enough — your brain needs to beat the trap on a fresh question. Practice the skill in the kaoshen.co question bank: miss one and it is logged with the exact error, then brought back to you three days later and again after fourteen.
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