13. Every Friday, milkshakes are on sale at The Ice Cream Shoppe with a 15% discount. 13a) The regular price of a milk shake is $4. What is the discount price?

13b) If the regular price of a shake is X dollars, what is the discount price in dollars?

13c) On your birthday, the discount price of an ice cream cake is $22. What is the regular price?

(*I really need help on this T^T*)

13a) $3.40

13b) 0.85X

13c) $25.88

Step-by-step explanation:

13a) When there is a 15% discount, we can say that we are only paying 85% of the original price because out of 100%, 15% is taken away. 85% in decimals is 85/100 = 0.85.

$4 x 0.85 is the discounted price, which is $3.40

13b) In 13a, the price was 4. Now, the price is X. Hence we plug in (substitute) X in for 4, giving us X x 0.85, which we can write as 0.85X

13c) 85% of the cake is $22. To find 100% of the price, we can find 1% of the original price and then multiply that by 100, which gives us 100% of the price.

We know 85% of the original price. Therefore, dividng the price by 85 will give us 1% of the price. 1% = $22/85

Finally, to calculate 100%, we multiply by 100.

22/88 x 100 = 440/17 which is 25.882 in decimals, which we round to 2 decimal places (because it is currency) = $25.88