In an ongoing sale at a mall, 50% + 30% discount is offered. What will be the new discount?

Here's how to figure it out without using an actual price.

When you take a 50% discount, there is 50% *remaining*.

When you take a 30% discount, there is 70% *remaining*.

Multiply these together to find the combined amount that is *remaining*:

0.5 * 0.7 = 0.35 --> 35%

Since the newly discounted price is 35% of the original, that means the combined discount must be 65%.

Mathematically to calculate the amount of multiple discounts, you would calculate:

1 - (1 - 0.50)(1 - 0.30)

= 1 - (0.50)(0.70)

= 1 - 0.35

= 0.65 <-- convert the decimal back to a percent --> 65%

Answer:

65%

The 50% discount makes the new price into 50% of the original price.

So 30% of the "new" price is 15% of the original price.

So applying that discount brings the new, new price down to 35% of the original price.

The reason why 100 seems to keep coming into it is that "percent" MEANS "hundredths."

Start with the $100 price.

Take 50% off of that. That gets you to $50.

Now, take 30% off of the $50. That chops another $15 off of the $50, so your final price is $35.