Let’s solve each question one by one, step by step.
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Question 1: What is the formula for calculating percentage discount?
We want to find the
sale price (S) after a discount.
- Let
p = original price
- Let
r = discount rate (as a decimal, like 0.25 for 25%)
The amount of discount is:
r × p
So, sale price = original price – discount
→ S = p - rp
That matches the first option.
✔ Correct answer:
S = p - rp
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Question 2: What is the final price of an item discounted at 45% off that normally sells for $65.00?
Step 1: Find the discount amount.
45% of $65 = 0.45 × 65
Let’s calculate that:
0.45 × 65 = ?
Break it down:
0.45 × 60 = 27
0.45 × 5 = 2.25
Total = 27 + 2.25 =
29.25
So, discount = $29.25
Step 2: Subtract from original price:
$65.00 - $29.25 =
$35.75
✔ Final price =
$35.75
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Question 3: Which expression shows the shortcut method to find 40% off $70.00?
“Shortcut method” means we don’t subtract the discount — instead, we multiply by what’s LEFT.
If you take 40% off, you pay 60% of the original price.
60% as a decimal = 0.6
So, sale price = 0.6 × 70 →
S = 0.6(70)
That’s the first option.
Check others:
- S = 70 - 0.4(70) → This is correct too, but it’s NOT the shortcut — it’s the long way.
- S = 0.6(70) - 0.4(70) → That would be subtracting twice — wrong.
- “None of these” → Not true, since first one is correct.
But note: The question says “shortcut method”. So even though both first and second are mathematically correct, the *shortcut* is multiplying by the remaining percent.
✔ Best answer:
S = 0.6(70)
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Final Answer:
1. S = p - rp
2. $35.75
3. S = 0.6(70)
Parent Tip: Review the logic above to help your child master the concept of percent discount worksheet.
