You have a coupon for an additional 25% off the price of any sale item at store. the store has put a robotics kit on sale for 15% off the original price of $40. what is the price of the robotics kits after both discounts?

Firstly we need to count how much is 15% from $40:

40 * 15% =
= 40 * 15/100 =
= 40 * 3/20 =
= 2 * 3/1 =
= 2 * 3 =
= 6 [dollars]

So the kit costed $40 - $6 = $34 after the first general discount. Now the question is if the coupon relates to the original price or to the lowered price. We'll do both:

If it relates to the original price, we need to find how much is 25% of $40. We can do it in mind - it's $10. So with two discounts the price would be $40 - $6 - $10 = $24.

However, if it relates to the lowered price, we need to find how much is 25% from $34:

34 * 25% =
= 34 * 25/100 =
= 34 * 1/4 =
= 8.5 [dollars]

So the final price in such a situation would be $40 - $6 - $8.5 = $25.5.