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

To find the change Tom should get, we subtract the total cost from the amount he pays:

Change = Amount paid - Total cost
Change = €20.00 - €6.67 = €13.33

Given the doubling ratio in ingredients for 24 cookies compared to 12 cookies:

• For milk: Since 12 cookies require 50 ml, for 24 cookies, it would be double:

  Milk (ml) for 24 cookies = 50 ml × 2 = 100 ml

• For butter, the amount required for 12 cookies can be calculated as follows:

  Butter (g) for 12 cookies = 180 g ÷ 2 = 90 g

The completed table looks like this:

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

Tom puts the cookies in the oven at 10:50 a.m. and checks the oven 15 minutes later:

Check time = 10:50 a.m. + 15 minutes = 11:05 a.m.

The volume of a cylinder is given by the formula:

$V = ext{π}r^2h$

where r is the radius and h is the height.
Here, the radius (r) = 10 cm / 2 = 5 cm and height (h) = 4 cm.

Substituting these values into the formula:

$V = ext{π}(5^2)(4) = ext{π}(25)(4) = 100 ext{π}$

So the volume of Tom's cake tin is $100 ext{π} ext{ cm}^3$.

Tom reduces the baking temperature of 210° by 10%.
First, we calculate 10% of 210°:

10% of 210° = 0.10 × 210° = 21°

Then, we subtract this value from the original temperature:

New temperature = 210° - 21° = 189°

Therefore, the temperature that Tom uses is 189°.