Solve multi-step percent word problems combining several percent ideas.
Free, timed SHSAT practice sets on multi-step percent problemsβ every question includes a full worked explanation, and there's no account required.
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Multi-step percent problems chain two or three simple percent steps. The key is to know which number each percent is taken of.
Example: a 50-dollar item is 20% off, and then 8% tax is added to the sale price: \(50 \times 0.80 \times 1.08 = 43.20\) dollars.
Traps:
Sale price \(= \$205.00 \times (1 - 4/100) = \$196.80\); tax \(= \$196.80 \times 8/100 = \$15.744 \approx \$15.74\); total \(= \$212.54\). (Figuring the tax on the original price (8% of \(\$205.00\) is $16.40) gives $213.20. Forgetting to add the tax gives $196.80. Subtracting the tax instead of adding it gives about $181.06.)
From step 1: 64% of the whole is 144, so the whole is \(144 \times 100 \div 64 = 225\) employees. Then 28% of 225 \(= 63\) employees signed up for chess club. (Stopping at the total number of employees gives 225. Finding the total with 36% instead of 64% (\(144 \times 100 \div 36\)) and then taking 28% of it gives 112. Finding the employees who did NOT sign up for chess club (\(225 - 63\)) gives 162.)
After growth: 6480 \(\times (1 + 10/100) = 7128\). After decline: 7128 \(\times (1 - 25/100) = 5346\). (Combining +10% and -25% into one 15% decrease of 6480 gives 5508. Stopping after the first year gives 7128. Reporting only the change in population (\(6480 - 5346\)) gives 1134.)