Rob has been asked to divide 120 in the ratio 3:5 Here is his working - Edexcel - GCSE Maths - Question 2 - 2022 - Paper 3

Rob has made a mistake in the way he approached dividing 120 into the ratio 3:5. He should have added the parts of the ratio first, which are 3 and 5, giving a total of:

$3 + 5 = 8$

Next, to find each part's value, he should have divided 120 by the total parts (8) first. Therefore, his calculation should have been:

$\frac{120}{8} = 15$

Now, to find each section of the ratio:

• For the 3 parts: $3 \times 15 = 45$
• For the 5 parts: $5 \times 15 = 75$

So, the correct division of 120 in the ratio 3:5 is 45 and 75. In summary, Rob did not add the two ratio parts together before dividing, which led to incorrect calculations.