Tom is baking for the school bake sale - Junior Cycle Mathematics - Question 2 - 2021

To find out how much change Tom gets after paying with a €20 note, we subtract the total cost from the amount paid:

Change = Amount paid - Total cost Change = €20 - €6.67

Calculating this gives:

$20 - 6.67 = 13.33$

So, Tom should get €13.33 in change.

To find the missing values:

• For the quantity of milk in 24 cookies, the ratio of ingredients is consistent. Since 12 cookies require 50 ml of milk, then for 24 cookies (which is double), it will be:

$50 ext{ ml} imes 2 = 100 ext{ ml}$

• To find the quantity of butter for 12 cookies, we know from the table for 24 cookies that it uses 180g. Therefore, for 12 cookies, it will be half:

180 ext{ g} imes rac{1}{2} = 90 ext{ g}

Thus, the table will then show:

Ingredient	12 cookies	24 cookies
Eggs	2	4
Milk (ml)	50	100
Butter (g)	90	180

If Tom puts the cookies in the oven at 10:50 a.m. and checks them 15 minutes later, we simply add 15 minutes to 10:50:

10:50 + 0:15 = 11:05

Thus, Tom checks the oven at 11:05 a.m..

To find the volume of a cylinder, we use the formula:

$V = ext{π}r^2h$

In this case, the height (h) of the cake tin is 4 cm, and the radius (r) is half of the diameter:

r = rac{10 ext{ cm}}{2} = 5 ext{ cm}

Substituting these values into the volume formula:

$V = ext{π}(5 ext{ cm})^2(4 ext{ cm})$

Calculating gives:

$V = ext{π}(25)(4) = 100 ext{π} ext{ cm}^3$

Thus, the volume of Tom's cake tin is 100π cm³.

To find the new temperature after a reduction of 10% from 210°:

First, we calculate 10% of 210°:

10 ext{% of } 210 = 0.1 imes 210 = 21

Now, we subtract this from the original temperature:

$210° - 21° = 189°$

Therefore, the new temperature that Tom uses is 189°.