Answer:

d. 15

Step-by-step explanation:

Problems involving ratios

In this problem, we are given the ratio of the unknown numbers of 1:2:3 and the sum of these numbers is 30. We need to calculate the largest number.

Step 1: Let x be the unknown number.  We can use the ratio to determine the three unknown numbers together with their sum. Hence,

1x + 2x + 3x = 30

6x = 30

6x/6 = 30/6

x = 5

Step 2: Use the resulting values of x to determine the three unknown numbers.

1x = 1 x 5 = 5

2x = 2 x 5 = 10

3x = 3 x 5 = 15

Therefore, the largest number is 15.

To learn more about problems involving ratios, click on the link below:

brainly.ph/question/8805213

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